--- a/devtools/client/netmonitor/har/test/browser_net_har_copy_all_as_har.js
+++ b/devtools/client/netmonitor/har/test/browser_net_har_copy_all_as_har.js
@@ -2,17 +2,17 @@
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
 /**
  * Basic tests for exporting Network panel content into HAR format.
  */
 add_task(function* () {
-  let [tab, , monitor ] = yield initNetMonitor(SIMPLE_URL);
+  let { tab, monitor } = yield initNetMonitor(SIMPLE_URL);
 
   info("Starting test... ");
 
   let { NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
 

--- a/devtools/client/netmonitor/har/test/browser_net_har_post_data.js
+++ b/devtools/client/netmonitor/har/test/browser_net_har_post_data.js
@@ -2,17 +2,17 @@
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
 /**
  * Tests for exporting POST data into HAR format.
  */
 add_task(function* () {
-  let [tab, , monitor ] = yield initNetMonitor(
+  let { tab, monitor } = yield initNetMonitor(
     HAR_EXAMPLE_URL + "html_har_post-data-test-page.html");
 
   info("Starting test... ");
 
   let { NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;

--- a/devtools/client/netmonitor/har/test/browser_net_har_throttle_upload.js
+++ b/devtools/client/netmonitor/har/test/browser_net_har_throttle_upload.js
@@ -6,17 +6,17 @@
 "use strict";
 
 add_task(function* () {
   yield throttleUploadTest(true);
   yield throttleUploadTest(false);
 });
 
 function* throttleUploadTest(actuallyThrottle) {
-  let [tab, , monitor ] = yield initNetMonitor(
+  let { tab, monitor } = yield initNetMonitor(
     HAR_EXAMPLE_URL + "html_har_post-data-test-page.html");
 
   info("Starting test... (actuallyThrottle = " + actuallyThrottle + ")");
 
   let { NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   const size = 4096;

--- a/devtools/client/netmonitor/test/browser_net_aaa_leaktest.js
+++ b/devtools/client/netmonitor/test/browser_net_aaa_leaktest.js
@@ -4,17 +4,17 @@
 "use strict";
 
 /**
  * Tests if the network monitor leaks on initialization and sudden destruction.
  * You can also use this initialization format as a template for other tests.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(SIMPLE_URL);
+  let { tab, monitor } = yield initNetMonitor(SIMPLE_URL);
   info("Starting test... ");
 
   let { document, NetMonitorView, NetMonitorController } = monitor.panelWin;
   let { RequestsMenu, NetworkDetails } = NetMonitorView;
 
   ok(tab, "Should have a tab available.");
   ok(monitor, "Should have a network monitor pane available.");
 

--- a/devtools/client/netmonitor/test/browser_net_accessibility-01.js
+++ b/devtools/client/netmonitor/test/browser_net_accessibility-01.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if focus modifiers work for the SideMenuWidget.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CUSTOM_GET_URL);
+  let { tab, monitor } = yield initNetMonitor(CUSTOM_GET_URL);
   info("Starting test... ");
 
   // It seems that this test may be slow on Ubuntu builds running on ec2.
   requestLongerTimeout(2);
 
   let { NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 

--- a/devtools/client/netmonitor/test/browser_net_accessibility-02.js
+++ b/devtools/client/netmonitor/test/browser_net_accessibility-02.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if keyboard and mouse navigation works in the network requests menu.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CUSTOM_GET_URL);
+  let { tab, monitor } = yield initNetMonitor(CUSTOM_GET_URL);
   info("Starting test... ");
 
   // It seems that this test may be slow on Ubuntu builds running on ec2.
   requestLongerTimeout(2);
 
   let { window, $, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 

--- a/devtools/client/netmonitor/test/browser_net_api-calls.js
+++ b/devtools/client/netmonitor/test/browser_net_api-calls.js
@@ -4,17 +4,17 @@
 "use strict";
 
 /**
  * Tests whether API call URLs (without a filename) are correctly displayed
  * (including Unicode)
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(API_CALLS_URL);
+  let { tab, monitor } = yield initNetMonitor(API_CALLS_URL);
   info("Starting test... ");
 
   let { NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
 
   const REQUEST_URIS = [

--- a/devtools/client/netmonitor/test/browser_net_autoscroll.js
+++ b/devtools/client/netmonitor/test/browser_net_autoscroll.js
@@ -4,17 +4,17 @@
 "use strict";
 
 /**
  * Bug 863102 - Automatically scroll down upon new network requests.
  */
 add_task(function* () {
   requestLongerTimeout(2);
 
-  let [, , monitor] = yield initNetMonitor(INFINITE_GET_URL);
+  let { monitor } = yield initNetMonitor(INFINITE_GET_URL);
   let win = monitor.panelWin;
   let topNode = win.document.getElementById("requests-menu-contents");
   let requestsContainer = topNode.getElementsByTagName("scrollbox")[0];
   ok(!!requestsContainer, "Container element exists as expected.");
 
   // (1) Check that the scroll position is maintained at the bottom
   // when the requests overflow the vertical size of the container.
   yield waitForRequestsToOverflowContainer();

--- a/devtools/client/netmonitor/test/browser_net_cached-status.js
+++ b/devtools/client/netmonitor/test/browser_net_cached-status.js
@@ -4,17 +4,17 @@
 
 "use strict";
 
 /**
  * Tests if cached requests have the correct status code
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(STATUS_CODES_URL, null, true);
+  let { tab, monitor } = yield initNetMonitor(STATUS_CODES_URL, null, true);
   info("Starting test... ");
 
   let { NetMonitorView } = monitor.panelWin;
   let { RequestsMenu, NetworkDetails } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
   NetworkDetails._params.lazyEmpty = false;
 

--- a/devtools/client/netmonitor/test/browser_net_cause.js
+++ b/devtools/client/netmonitor/test/browser_net_cause.js
@@ -79,17 +79,17 @@ const EXPECTED_REQUESTS = [
 
 add_task(function* () {
   // the initNetMonitor function clears the network request list after the
   // page is loaded. That's why we first load a bogus page from SIMPLE_URL,
   // and only then load the real thing from CAUSE_URL - we want to catch
   // all the requests the page is making, not only the XHRs.
   // We can't use about:blank here, because initNetMonitor checks that the
   // page has actually made at least one request.
-  let [tab, , monitor] = yield initNetMonitor(SIMPLE_URL);
+  let { tab, monitor } = yield initNetMonitor(SIMPLE_URL);
   let { $, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
   RequestsMenu.lazyUpdate = false;
 
   let wait = waitForNetworkEvents(monitor, EXPECTED_REQUESTS.length);
   tab.linkedBrowser.loadURI(CAUSE_URL);
   yield wait;
 

--- a/devtools/client/netmonitor/test/browser_net_cause_redirect.js
+++ b/devtools/client/netmonitor/test/browser_net_cause_redirect.js
@@ -13,17 +13,17 @@ add_task(function* () {
     // Request to HTTP URL, redirects to HTTPS, has callstack
     { status: 302, hasStack: true },
     // Serves HTTPS, sets the Strict-Transport-Security header, no stack
     { status: 200, hasStack: false },
     // Second request to HTTP redirects to HTTPS internally
     { status: 200, hasStack: true },
   ];
 
-  let [tab, , monitor] = yield initNetMonitor(CUSTOM_GET_URL);
+  let { tab, monitor } = yield initNetMonitor(CUSTOM_GET_URL);
   let { RequestsMenu } = monitor.panelWin.NetMonitorView;
   RequestsMenu.lazyUpdate = false;
 
   let wait = waitForNetworkEvents(monitor, EXPECTED_REQUESTS.length);
   yield performRequests(2, HSTS_SJS);
   yield wait;
 
   EXPECTED_REQUESTS.forEach(({status, hasStack}, i) => {

--- a/devtools/client/netmonitor/test/browser_net_charts-01.js
+++ b/devtools/client/netmonitor/test/browser_net_charts-01.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Makes sure Pie Charts have the right internal structure.
  */
 
 add_task(function* () {
-  let [, , monitor] = yield initNetMonitor(SIMPLE_URL);
+  let { monitor } = yield initNetMonitor(SIMPLE_URL);
   info("Starting test... ");
 
   let { document, Chart } = monitor.panelWin;
 
   let pie = Chart.Pie(document, {
     width: 100,
     height: 100,
     data: [{

--- a/devtools/client/netmonitor/test/browser_net_charts-02.js
+++ b/devtools/client/netmonitor/test/browser_net_charts-02.js
@@ -4,17 +4,17 @@
 "use strict";
 
 /**
  * Makes sure Pie Charts have the right internal structure when
  * initialized with empty data.
  */
 
 add_task(function* () {
-  let [, , monitor] = yield initNetMonitor(SIMPLE_URL);
+  let { monitor } = yield initNetMonitor(SIMPLE_URL);
   info("Starting test... ");
 
   let { document, L10N, Chart } = monitor.panelWin;
 
   let pie = Chart.Pie(document, {
     data: null,
     width: 100,
     height: 100

--- a/devtools/client/netmonitor/test/browser_net_charts-03.js
+++ b/devtools/client/netmonitor/test/browser_net_charts-03.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Makes sure Table Charts have the right internal structure.
  */
 
 add_task(function* () {
-  let [, , monitor] = yield initNetMonitor(SIMPLE_URL);
+  let { monitor } = yield initNetMonitor(SIMPLE_URL);
   info("Starting test... ");
 
   let { document, L10N, Chart } = monitor.panelWin;
 
   let table = Chart.Table(document, {
     title: "Table title",
     data: [{
       label1: 1,

--- a/devtools/client/netmonitor/test/browser_net_charts-04.js
+++ b/devtools/client/netmonitor/test/browser_net_charts-04.js
@@ -4,17 +4,17 @@
 "use strict";
 
 /**
  * Makes sure Pie Charts have the right internal structure when
  * initialized with empty data.
  */
 
 add_task(function* () {
-  let [, , monitor] = yield initNetMonitor(SIMPLE_URL);
+  let { monitor } = yield initNetMonitor(SIMPLE_URL);
   info("Starting test... ");
 
   let { document, L10N, Chart } = monitor.panelWin;
 
   let table = Chart.Table(document, {
     title: "Table title",
     data: null,
     totals: {

--- a/devtools/client/netmonitor/test/browser_net_charts-05.js
+++ b/devtools/client/netmonitor/test/browser_net_charts-05.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Makes sure Pie+Table Charts have the right internal structure.
  */
 
 add_task(function* () {
-  let [, , monitor] = yield initNetMonitor(SIMPLE_URL);
+  let { monitor } = yield initNetMonitor(SIMPLE_URL);
   info("Starting test... ");
 
   let { document, L10N, Chart } = monitor.panelWin;
 
   let chart = Chart.PieTable(document, {
     title: "Table title",
     data: [{
       size: 1,

--- a/devtools/client/netmonitor/test/browser_net_charts-06.js
+++ b/devtools/client/netmonitor/test/browser_net_charts-06.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Makes sure Pie Charts correctly handle empty source data.
  */
 
 add_task(function* () {
-  let [, , monitor] = yield initNetMonitor(SIMPLE_URL);
+  let { monitor } = yield initNetMonitor(SIMPLE_URL);
   info("Starting test... ");
 
   let { document, L10N, Chart } = monitor.panelWin;
 
   let pie = Chart.Pie(document, {
     data: [],
     width: 100,
     height: 100

--- a/devtools/client/netmonitor/test/browser_net_charts-07.js
+++ b/devtools/client/netmonitor/test/browser_net_charts-07.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Makes sure Table Charts correctly handle empty source data.
  */
 
 add_task(function* () {
-  let [, , monitor] = yield initNetMonitor(SIMPLE_URL);
+  let { monitor } = yield initNetMonitor(SIMPLE_URL);
   info("Starting test... ");
 
   let { document, L10N, Chart } = monitor.panelWin;
 
   let table = Chart.Table(document, {
     data: [],
     totals: {
       label1: value => "Hello " + L10N.numberWithDecimals(value, 2),

--- a/devtools/client/netmonitor/test/browser_net_clear.js
+++ b/devtools/client/netmonitor/test/browser_net_clear.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if the clear button empties the request menu.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(SIMPLE_URL);
+  let { tab, monitor } = yield initNetMonitor(SIMPLE_URL);
   info("Starting test... ");
 
   let { $, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
   let detailsPane = $("#details-pane");
   let detailsPaneToggleButton = $("#details-pane-toggle");
   let clearButton = $("#requests-menu-clear-button");
 

--- a/devtools/client/netmonitor/test/browser_net_complex-params.js
+++ b/devtools/client/netmonitor/test/browser_net_complex-params.js
@@ -4,17 +4,17 @@
 "use strict";
 
 /**
  * Tests whether complex request params and payload sent via POST are
  * displayed correctly.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(PARAMS_URL);
+  let { tab, monitor } = yield initNetMonitor(PARAMS_URL);
   info("Starting test... ");
 
   let { document, L10N, EVENTS, Editor, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu, NetworkDetails } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
   NetworkDetails._params.lazyEmpty = false;
 

--- a/devtools/client/netmonitor/test/browser_net_content-type.js
+++ b/devtools/client/netmonitor/test/browser_net_content-type.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if different response content types are handled correctly.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CONTENT_TYPE_WITHOUT_CACHE_URL);
+  let { tab, monitor } = yield initNetMonitor(CONTENT_TYPE_WITHOUT_CACHE_URL);
   info("Starting test... ");
 
   let { document, L10N, Editor, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
 
   let wait = waitForNetworkEvents(monitor, 7);

--- a/devtools/client/netmonitor/test/browser_net_copy_as_curl.js
+++ b/devtools/client/netmonitor/test/browser_net_copy_as_curl.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if Copy as cURL works.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CURL_URL);
+  let { tab, monitor } = yield initNetMonitor(CURL_URL);
   info("Starting test... ");
 
   // Different quote chars are used for Windows and POSIX
   const QUOTE = Services.appinfo.OS == "WINNT" ? "\"" : "'";
 
   // Quote a string, escape the quotes inside the string
   function quote(str) {
     return QUOTE + str.replace(new RegExp(QUOTE, "g"), `\\${QUOTE}`) + QUOTE;

--- a/devtools/client/netmonitor/test/browser_net_copy_headers.js
+++ b/devtools/client/netmonitor/test/browser_net_copy_headers.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if copying a request's request/response headers works.
  */
 
 add_task(function* () {
-  let [tab, , monitor ] = yield initNetMonitor(SIMPLE_URL);
+  let { tab, monitor } = yield initNetMonitor(SIMPLE_URL);
   info("Starting test... ");
 
   let { NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
 
   let wait = waitForNetworkEvents(monitor, 1);

--- a/devtools/client/netmonitor/test/browser_net_copy_image_as_data_uri.js
+++ b/devtools/client/netmonitor/test/browser_net_copy_image_as_data_uri.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if copying an image as data uri works.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CONTENT_TYPE_WITHOUT_CACHE_URL);
+  let { tab, monitor } = yield initNetMonitor(CONTENT_TYPE_WITHOUT_CACHE_URL);
   info("Starting test... ");
 
   let { NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
 
   let wait = waitForNetworkEvents(monitor, 7);

--- a/devtools/client/netmonitor/test/browser_net_copy_params.js
+++ b/devtools/client/netmonitor/test/browser_net_copy_params.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests whether copying a request item's parameters works.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(PARAMS_URL);
+  let { tab, monitor } = yield initNetMonitor(PARAMS_URL);
   info("Starting test... ");
 
   let { document, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
 
   let wait = waitForNetworkEvents(monitor, 1, 6);

--- a/devtools/client/netmonitor/test/browser_net_copy_response.js
+++ b/devtools/client/netmonitor/test/browser_net_copy_response.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if copying a request's response works.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CONTENT_TYPE_WITHOUT_CACHE_URL);
+  let { tab, monitor } = yield initNetMonitor(CONTENT_TYPE_WITHOUT_CACHE_URL);
   info("Starting test... ");
 
   const EXPECTED_RESULT = '{ "greeting": "Hello JSON!" }';
 
   let { NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;

--- a/devtools/client/netmonitor/test/browser_net_copy_svg_image_as_data_uri.js
+++ b/devtools/client/netmonitor/test/browser_net_copy_svg_image_as_data_uri.js
@@ -5,17 +5,17 @@
 
 /**
  * Tests if copying an image as data uri works.
  */
 
 const SVG_URL = EXAMPLE_URL + "dropmarker.svg";
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CURL_URL);
+  let { tab, monitor } = yield initNetMonitor(CURL_URL);
   info("Starting test... ");
 
   let { NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
 
   let wait = waitForNetworkEvents(monitor, 1);

--- a/devtools/client/netmonitor/test/browser_net_copy_url.js
+++ b/devtools/client/netmonitor/test/browser_net_copy_url.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if copying a request's url works.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CUSTOM_GET_URL);
+  let { tab, monitor } = yield initNetMonitor(CUSTOM_GET_URL);
   info("Starting test... ");
 
   let { NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   let wait = waitForNetworkEvents(monitor, 1);
   yield ContentTask.spawn(tab.linkedBrowser, {}, function* () {
     content.wrappedJSObject.performRequests(1);

--- a/devtools/client/netmonitor/test/browser_net_cors_requests.js
+++ b/devtools/client/netmonitor/test/browser_net_cors_requests.js
@@ -4,17 +4,17 @@
 
 "use strict";
 
 /**
  * Test that CORS preflight requests are displayed by network monitor
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CORS_URL);
+  let { tab, monitor } = yield initNetMonitor(CORS_URL);
   let { RequestsMenu } = monitor.panelWin.NetMonitorView;
   RequestsMenu.lazyUpdate = false;
 
   let wait = waitForNetworkEvents(monitor, 1, 1);
 
   info("Performing a CORS request");
   let requestUrl = "http://test1.example.com" + CORS_SJS_PATH;
   yield ContentTask.spawn(tab.linkedBrowser, requestUrl, function* (url) {

--- a/devtools/client/netmonitor/test/browser_net_curl-utils.js
+++ b/devtools/client/netmonitor/test/browser_net_curl-utils.js
@@ -5,17 +5,17 @@
 
 /**
  * Tests Curl Utils functionality.
  */
 
 const { CurlUtils } = require("devtools/client/shared/curl");
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CURL_UTILS_URL);
+  let { tab, monitor } = yield initNetMonitor(CURL_UTILS_URL);
   info("Starting test... ");
 
   let { NetMonitorView, gNetwork } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
 
   let wait = waitForNetworkEvents(monitor, 1, 3);

--- a/devtools/client/netmonitor/test/browser_net_cyrillic-01.js
+++ b/devtools/client/netmonitor/test/browser_net_cyrillic-01.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if cyrillic text is rendered correctly in the source editor.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CYRILLIC_URL);
+  let { tab, monitor } = yield initNetMonitor(CYRILLIC_URL);
   info("Starting test... ");
 
   let { document, EVENTS, Editor, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
 
   let wait = waitForNetworkEvents(monitor, 1);

--- a/devtools/client/netmonitor/test/browser_net_cyrillic-02.js
+++ b/devtools/client/netmonitor/test/browser_net_cyrillic-02.js
@@ -4,17 +4,17 @@
 "use strict";
 
 /**
  * Tests if cyrillic text is rendered correctly in the source editor
  * when loaded directly from an HTML page.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CYRILLIC_URL);
+  let { tab, monitor } = yield initNetMonitor(CYRILLIC_URL);
   info("Starting test... ");
 
   let { document, EVENTS, Editor, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
 
   let wait = waitForNetworkEvents(monitor, 1);

--- a/devtools/client/netmonitor/test/browser_net_details-no-duplicated-content.js
+++ b/devtools/client/netmonitor/test/browser_net_details-no-duplicated-content.js
@@ -2,17 +2,17 @@
 /* Any copyright is dedicated to the Public Domain.
  http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
 // A test to ensure that the content in details pane is not duplicated.
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CUSTOM_GET_URL);
+  let { tab, monitor } = yield initNetMonitor(CUSTOM_GET_URL);
   let panel = monitor.panelWin;
   let { NetMonitorView, EVENTS } = panel;
   let { RequestsMenu, NetworkDetails } = NetMonitorView;
 
   const COOKIE_UNIQUE_PATH = "/do-not-use-in-other-tests-using-cookies";
 
   let TEST_CASES = [
     {

--- a/devtools/client/netmonitor/test/browser_net_filter-01.js
+++ b/devtools/client/netmonitor/test/browser_net_filter-01.js
@@ -24,17 +24,17 @@ const REQUESTS_WITH_MEDIA_AND_FLASH = RE
 ]);
 
 const REQUESTS_WITH_MEDIA_AND_FLASH_AND_WS = REQUESTS_WITH_MEDIA_AND_FLASH.concat([
   /* "Upgrade" is a reserved header and can not be set on XMLHttpRequest */
   { url: "sjs_content-type-test-server.sjs?fmt=ws" },
 ]);
 
 add_task(function* () {
-  let [,, monitor] = yield initNetMonitor(FILTERING_URL);
+  let { monitor } = yield initNetMonitor(FILTERING_URL);
 
   function setFreetextFilter(value) {
     // Set the text and manually call all callbacks synchronously to avoid the timeout
     RequestsMenu.freetextFilterBox.value = value;
     RequestsMenu.requestsFreetextFilterEvent();
     RequestsMenu.userInputTimer.cancel();
     RequestsMenu.reFilterRequests();
   }

--- a/devtools/client/netmonitor/test/browser_net_filter-02.js
+++ b/devtools/client/netmonitor/test/browser_net_filter-02.js
@@ -25,17 +25,17 @@ const REQUESTS_WITH_MEDIA_AND_FLASH = RE
 ]);
 
 const REQUESTS_WITH_MEDIA_AND_FLASH_AND_WS = REQUESTS_WITH_MEDIA_AND_FLASH.concat([
   /* "Upgrade" is a reserved header and can not be set on XMLHttpRequest */
   { url: "sjs_content-type-test-server.sjs?fmt=ws" },
 ]);
 
 add_task(function* () {
-  let [,, monitor] = yield initNetMonitor(FILTERING_URL);
+  let { monitor } = yield initNetMonitor(FILTERING_URL);
   info("Starting test... ");
 
   // It seems that this test may be slow on Ubuntu builds running on ec2.
   requestLongerTimeout(2);
 
   let { $, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 

--- a/devtools/client/netmonitor/test/browser_net_filter-03.js
+++ b/devtools/client/netmonitor/test/browser_net_filter-03.js
@@ -16,17 +16,17 @@ const BASIC_REQUESTS = [
 const REQUESTS_WITH_MEDIA = BASIC_REQUESTS.concat([
   { url: "sjs_content-type-test-server.sjs?fmt=font" },
   { url: "sjs_content-type-test-server.sjs?fmt=image" },
   { url: "sjs_content-type-test-server.sjs?fmt=audio" },
   { url: "sjs_content-type-test-server.sjs?fmt=video" },
 ]);
 
 add_task(function* () {
-  let [,, monitor] = yield initNetMonitor(FILTERING_URL);
+  let { monitor } = yield initNetMonitor(FILTERING_URL);
   info("Starting test... ");
 
   // It seems that this test may be slow on Ubuntu builds running on ec2.
   requestLongerTimeout(2);
 
   let { $, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 

--- a/devtools/client/netmonitor/test/browser_net_filter-04.js
+++ b/devtools/client/netmonitor/test/browser_net_filter-04.js
@@ -27,17 +27,17 @@ const REQUESTS_WITH_MEDIA_AND_FLASH = RE
 const REQUESTS_WITH_MEDIA_AND_FLASH_AND_WS = REQUESTS_WITH_MEDIA_AND_FLASH.concat([
   /* "Upgrade" is a reserved header and can not be set on XMLHttpRequest */
   { url: "sjs_content-type-test-server.sjs?fmt=ws" },
 ]);
 
 add_task(function* () {
   Services.prefs.setCharPref("devtools.netmonitor.filters", '["js", "bogus"]');
 
-  let [,, monitor] = yield initNetMonitor(FILTERING_URL);
+  let { monitor } = yield initNetMonitor(FILTERING_URL);
   info("Starting test... ");
 
   let { Prefs, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
 
   is(Prefs.filters.length, 2,

--- a/devtools/client/netmonitor/test/browser_net_footer-summary.js
+++ b/devtools/client/netmonitor/test/browser_net_footer-summary.js
@@ -7,17 +7,17 @@
  * Test if the summary text displayed in the network requests menu footer
  * is correct.
  */
 
 add_task(function* () {
   requestLongerTimeout(2);
   let { PluralForm } = Cu.import("resource://gre/modules/PluralForm.jsm", {});
 
-  let [tab,, monitor] = yield initNetMonitor(FILTERING_URL);
+  let { tab, monitor } = yield initNetMonitor(FILTERING_URL);
   info("Starting test... ");
 
   let { $, L10N, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
   testStatus();
 

--- a/devtools/client/netmonitor/test/browser_net_frame.js
+++ b/devtools/client/netmonitor/test/browser_net_frame.js
@@ -148,17 +148,17 @@ const REQUEST_COUNT = EXPECTED_REQUESTS_
 
 add_task(function* () {
   // the initNetMonitor function clears the network request list after the
   // page is loaded. That's why we first load a bogus page from SIMPLE_URL,
   // and only then load the real thing from TOP_URL - we want to catch
   // all the requests the page is making, not only the XHRs.
   // We can't use about:blank here, because initNetMonitor checks that the
   // page has actually made at least one request.
-  let [ tab, , monitor ] = yield initNetMonitor(SIMPLE_URL);
+  let { tab, monitor } = yield initNetMonitor(SIMPLE_URL);
   let { NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
   RequestsMenu.lazyUpdate = false;
 
   tab.linkedBrowser.loadURI(TOP_URL, null, null);
 
   yield waitForNetworkEvents(monitor, REQUEST_COUNT);
 

--- a/devtools/client/netmonitor/test/browser_net_html-preview.js
+++ b/devtools/client/netmonitor/test/browser_net_html-preview.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if html responses show and properly populate a "Preview" tab.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CONTENT_TYPE_URL);
+  let { tab, monitor } = yield initNetMonitor(CONTENT_TYPE_URL);
   info("Starting test... ");
 
   let { $, document, EVENTS, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
 
   let wait = waitForNetworkEvents(monitor, 6);

--- a/devtools/client/netmonitor/test/browser_net_icon-preview.js
+++ b/devtools/client/netmonitor/test/browser_net_icon-preview.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if image responses show a thumbnail in the requests menu.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CONTENT_TYPE_WITHOUT_CACHE_URL);
+  let { tab, monitor } = yield initNetMonitor(CONTENT_TYPE_WITHOUT_CACHE_URL);
   info("Starting test... ");
 
   let { $, $all, EVENTS, ACTIVITY_TYPE, NetMonitorView, NetMonitorController } =
     monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   let wait = waitForEvents();
   yield performRequests();

--- a/devtools/client/netmonitor/test/browser_net_image-tooltip.js
+++ b/devtools/client/netmonitor/test/browser_net_image-tooltip.js
@@ -2,17 +2,17 @@
    http://creativecommons.org/publicdomain/zero/1.0/ */
 
 "use strict";
 
 /**
  * Tests if image responses show a popup in the requests menu when hovered.
  */
 add_task(function* test() {
-  let [tab, , monitor] = yield initNetMonitor(CONTENT_TYPE_WITHOUT_CACHE_URL);
+  let { tab, monitor } = yield initNetMonitor(CONTENT_TYPE_WITHOUT_CACHE_URL);
   info("Starting test... ");
 
   let { $, EVENTS, ACTIVITY_TYPE, NetMonitorView, NetMonitorController } =
     monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
   RequestsMenu.lazyUpdate = true;
 
   let onEvents = waitForNetworkEvents(monitor, 7);

--- a/devtools/client/netmonitor/test/browser_net_json-long.js
+++ b/devtools/client/netmonitor/test/browser_net_json-long.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if very long JSON responses are handled correctly.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(JSON_LONG_URL);
+  let { tab, monitor } = yield initNetMonitor(JSON_LONG_URL);
   info("Starting test... ");
 
   // This is receiving over 80 KB of json and will populate over 6000 items
   // in a variables view instance. Debug builds are slow.
   requestLongerTimeout(4);
 
   let { document, EVENTS, L10N, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;

--- a/devtools/client/netmonitor/test/browser_net_json-malformed.js
+++ b/devtools/client/netmonitor/test/browser_net_json-malformed.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if malformed JSON responses are handled correctly.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(JSON_MALFORMED_URL);
+  let { tab, monitor } = yield initNetMonitor(JSON_MALFORMED_URL);
   info("Starting test... ");
 
   let { document, EVENTS, Editor, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
 
   let wait = waitForNetworkEvents(monitor, 1);

--- a/devtools/client/netmonitor/test/browser_net_json_custom_mime.js
+++ b/devtools/client/netmonitor/test/browser_net_json_custom_mime.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if JSON responses with unusal/custom MIME types are handled correctly.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(JSON_CUSTOM_MIME_URL);
+  let { tab, monitor } = yield initNetMonitor(JSON_CUSTOM_MIME_URL);
   info("Starting test... ");
 
   let { document, EVENTS, L10N, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
 
   let wait = waitForNetworkEvents(monitor, 1);

--- a/devtools/client/netmonitor/test/browser_net_json_text_mime.js
+++ b/devtools/client/netmonitor/test/browser_net_json_text_mime.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if JSON responses with unusal/custom MIME types are handled correctly.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(JSON_TEXT_MIME_URL);
+  let { tab, monitor } = yield initNetMonitor(JSON_TEXT_MIME_URL);
   info("Starting test... ");
 
   let { document, EVENTS, L10N, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
 
   let wait = waitForNetworkEvents(monitor, 1);

--- a/devtools/client/netmonitor/test/browser_net_jsonp.js
+++ b/devtools/client/netmonitor/test/browser_net_jsonp.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if JSONP responses are handled correctly.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(JSONP_URL);
+  let { tab, monitor } = yield initNetMonitor(JSONP_URL);
   info("Starting test... ");
 
   let { document, EVENTS, L10N, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu, NetworkDetails } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
   NetworkDetails._json.lazyEmpty = false;
 

--- a/devtools/client/netmonitor/test/browser_net_large-response.js
+++ b/devtools/client/netmonitor/test/browser_net_large-response.js
@@ -5,17 +5,17 @@
 
 /**
  * Tests if very large response contents are just displayed as plain text.
  */
 
 const HTML_LONG_URL = CONTENT_TYPE_SJS + "?fmt=html-long";
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CUSTOM_GET_URL);
+  let { tab, monitor } = yield initNetMonitor(CUSTOM_GET_URL);
   info("Starting test... ");
 
   // This test could potentially be slow because over 100 KB of stuff
   // is going to be requested and displayed in the source editor.
   requestLongerTimeout(2);
 
   let { document, EVENTS, Editor, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;

--- a/devtools/client/netmonitor/test/browser_net_leak_on_tab_close.js
+++ b/devtools/client/netmonitor/test/browser_net_leak_on_tab_close.js
@@ -6,12 +6,12 @@
 /**
  * Tests that netmonitor doesn't leak windows on parent-side pages (bug 1285638)
  */
 
 add_task(function* () {
   // Tell initNetMonitor to enable cache. Otherwise it will assert that there were more
   // than zero network requests during the page load. But when loading about:config,
   // there are none.
-  let [,, monitor] = yield initNetMonitor("about:config", null, true);
+  let { monitor } = yield initNetMonitor("about:config", null, true);
   ok(monitor, "The network monitor was opened");
   yield teardown(monitor);
 });

--- a/devtools/client/netmonitor/test/browser_net_open_request_in_tab.js
+++ b/devtools/client/netmonitor/test/browser_net_open_request_in_tab.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if Open in new tab works.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CUSTOM_GET_URL);
+  let { tab, monitor } = yield initNetMonitor(CUSTOM_GET_URL);
   info("Starting test...");
 
   let { NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
 
   let wait = waitForNetworkEvents(monitor, 1);

--- a/devtools/client/netmonitor/test/browser_net_page-nav.js
+++ b/devtools/client/netmonitor/test/browser_net_page-nav.js
@@ -4,17 +4,17 @@
 "use strict";
 
 /**
  * Tests if page navigation ("close", "navigate", etc.) triggers an appropriate
  * action in the network monitor.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(SIMPLE_URL);
+  let { tab, monitor } = yield initNetMonitor(SIMPLE_URL);
   info("Starting test... ");
 
   let { EVENTS } = monitor.panelWin;
 
   yield testNavigate();
   yield testNavigateBack();
   yield testClose();
 

--- a/devtools/client/netmonitor/test/browser_net_pane-collapse.js
+++ b/devtools/client/netmonitor/test/browser_net_pane-collapse.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if the network monitor panes collapse properly.
  */
 
 add_task(function* () {
-  let [,, monitor] = yield initNetMonitor(SIMPLE_URL);
+  let { monitor } = yield initNetMonitor(SIMPLE_URL);
   info("Starting test... ");
 
   let { document, Prefs, NetMonitorView } = monitor.panelWin;
   let detailsPane = document.getElementById("details-pane");
   let detailsPaneToggleButton = document.getElementById("details-pane-toggle");
 
   ok(detailsPane.classList.contains("pane-collapsed") &&
      detailsPaneToggleButton.classList.contains("pane-collapsed"),

--- a/devtools/client/netmonitor/test/browser_net_pane-toggle.js
+++ b/devtools/client/netmonitor/test/browser_net_pane-toggle.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if toggling the details pane works as expected.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(SIMPLE_URL);
+  let { tab, monitor } = yield initNetMonitor(SIMPLE_URL);
   info("Starting test... ");
 
   let { $, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
   let { NETWORK_EVENT, TAB_UPDATED } = monitor.panelWin.EVENTS;
   RequestsMenu.lazyUpdate = false;
 
   let toggleButton = $("#details-pane-toggle");

--- a/devtools/client/netmonitor/test/browser_net_persistent_logs.js
+++ b/devtools/client/netmonitor/test/browser_net_persistent_logs.js
@@ -4,17 +4,17 @@
 "use strict";
 
 /**
  * Tests if the network monitor leaks on initialization and sudden destruction.
  * You can also use this initialization format as a template for other tests.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(SINGLE_GET_URL);
+  let { tab, monitor } = yield initNetMonitor(SINGLE_GET_URL);
   info("Starting test... ");
 
   let { NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   Services.prefs.setBoolPref("devtools.webconsole.persistlog", false);
 
   yield reloadAndWait();

--- a/devtools/client/netmonitor/test/browser_net_post-data-01.js
+++ b/devtools/client/netmonitor/test/browser_net_post-data-01.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if the POST requests display the correct information in the UI.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(POST_DATA_URL);
+  let { tab, monitor } = yield initNetMonitor(POST_DATA_URL);
   info("Starting test... ");
 
   let { document, EVENTS, L10N, Editor, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu, NetworkDetails } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
   NetworkDetails._params.lazyEmpty = false;
 

--- a/devtools/client/netmonitor/test/browser_net_post-data-02.js
+++ b/devtools/client/netmonitor/test/browser_net_post-data-02.js
@@ -4,17 +4,17 @@
 "use strict";
 
 /**
  * Tests if the POST requests display the correct information in the UI,
  * for raw payloads with attached content-type headers.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(POST_RAW_URL);
+  let { tab, monitor } = yield initNetMonitor(POST_RAW_URL);
   info("Starting test... ");
 
   let { document, EVENTS, L10N, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu, NetworkDetails } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
   NetworkDetails._params.lazyEmpty = false;
 

--- a/devtools/client/netmonitor/test/browser_net_post-data-03.js
+++ b/devtools/client/netmonitor/test/browser_net_post-data-03.js
@@ -4,17 +4,17 @@
 "use strict";
 
 /**
  * Tests if the POST requests display the correct information in the UI,
  * for raw payloads with content-type headers attached to the upload stream.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(POST_RAW_WITH_HEADERS_URL);
+  let { tab, monitor } = yield initNetMonitor(POST_RAW_WITH_HEADERS_URL);
   info("Starting test... ");
 
   let { document, EVENTS, L10N, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
 
   let wait = waitForNetworkEvents(monitor, 0, 1);

--- a/devtools/client/netmonitor/test/browser_net_prefs-and-l10n.js
+++ b/devtools/client/netmonitor/test/browser_net_prefs-and-l10n.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if the preferences and localization objects work correctly.
  */
 
 add_task(function* () {
-  let [,, monitor] = yield initNetMonitor(SIMPLE_URL);
+  let { monitor } = yield initNetMonitor(SIMPLE_URL);
   info("Starting test... ");
 
   ok(monitor.panelWin.L10N,
     "Should have a localization object available on the panel window.");
   ok(monitor.panelWin.Prefs,
     "Should have a preferences object available on the panel window.");
 
   testL10N();

--- a/devtools/client/netmonitor/test/browser_net_prefs-reload.js
+++ b/devtools/client/netmonitor/test/browser_net_prefs-reload.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if the prefs that should survive across tool reloads work.
  */
 
 add_task(function* () {
-  let [,, monitor] = yield initNetMonitor(SIMPLE_URL);
+  let { monitor } = yield initNetMonitor(SIMPLE_URL);
   info("Starting test... ");
 
   // This test reopens the network monitor a bunch of times, for different
   // hosts (bottom, side, window). This seems to be slow on debug builds.
   requestLongerTimeout(3);
 
   // Use these getters instead of caching instances inside the panel win,
   // since the tool is reopened a bunch of times during this test
@@ -141,72 +141,72 @@ add_task(function* () {
   function* testBottom() {
     info("Testing prefs reload for a bottom host.");
     storeFirstPrefValues();
 
     // Validate and modify while toolbox is on the bottom.
     validateFirstPrefValues();
     modifyFrontend();
 
-    let [,, newMonitor] = yield restartNetMonitor(monitor);
-    monitor = newMonitor;
+    let newMonitor = yield restartNetMonitor(monitor);
+    monitor = newMonitor.monitor;
 
     // Revalidate and reset frontend while toolbox is on the bottom.
     validateNewPrefValues();
     resetFrontend();
 
-    let [,, newMonitor2] = yield restartNetMonitor(monitor);
-    monitor = newMonitor2;
+    newMonitor = yield restartNetMonitor(monitor);
+    monitor = newMonitor.monitor;
 
     // Revalidate.
     validateFirstPrefValues();
   }
 
   function* testSide() {
     info("Moving toolbox to the side...");
 
     yield monitor._toolbox.switchHost(Toolbox.HostType.SIDE);
     info("Testing prefs reload for a side host.");
     storeFirstPrefValues();
 
     // Validate and modify frontend while toolbox is on the side.
     validateFirstPrefValues();
     modifyFrontend();
 
-    let [,, newMonitor] = yield restartNetMonitor(monitor);
-    monitor = newMonitor;
+    let newMonitor = yield restartNetMonitor(monitor);
+    monitor = newMonitor.monitor;
 
     // Revalidate and reset frontend while toolbox is on the side.
     validateNewPrefValues();
     resetFrontend();
 
-    let [,, newMonitor2] = yield restartNetMonitor(monitor);
-    monitor = newMonitor2;
+    newMonitor = yield restartNetMonitor(monitor);
+    monitor = newMonitor.monitor;
 
     // Revalidate.
     validateFirstPrefValues();
   }
 
   function* testWindow() {
     info("Moving toolbox into a window...");
 
     yield monitor._toolbox.switchHost(Toolbox.HostType.WINDOW);
     info("Testing prefs reload for a window host.");
     storeFirstPrefValues();
 
     // Validate and modify frontend while toolbox is in a window.
     validateFirstPrefValues();
     modifyFrontend();
 
-    let [,, newMonitor] = yield restartNetMonitor(monitor);
-    monitor = newMonitor;
+    let newMonitor = yield restartNetMonitor(monitor);
+    monitor = newMonitor.monitor;
 
     // Revalidate and reset frontend while toolbox is in a window.
     validateNewPrefValues();
     resetFrontend();
 
-    let [,, newMonitor2] = yield restartNetMonitor(monitor);
-    monitor = newMonitor2;
+    newMonitor = yield restartNetMonitor(monitor);
+    monitor = newMonitor.monitor;
 
     // Revalidate.
     validateFirstPrefValues();
   }
 });

--- a/devtools/client/netmonitor/test/browser_net_raw_headers.js
+++ b/devtools/client/netmonitor/test/browser_net_raw_headers.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if showing raw headers works.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(POST_DATA_URL);
+  let { tab, monitor } = yield initNetMonitor(POST_DATA_URL);
   info("Starting test... ");
 
   let { document, EVENTS, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
 
   let wait = waitForNetworkEvents(monitor, 0, 2);

--- a/devtools/client/netmonitor/test/browser_net_reload-button.js
+++ b/devtools/client/netmonitor/test/browser_net_reload-button.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if the empty-requests reload button works.
  */
 
 add_task(function* () {
-  let [,, monitor] = yield initNetMonitor(SINGLE_GET_URL);
+  let { monitor } = yield initNetMonitor(SINGLE_GET_URL);
   info("Starting test... ");
 
   let { document, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   let wait = waitForNetworkEvents(monitor, 2);
   let button = document.querySelector("#requests-menu-reload-notice-button");
   button.click();

--- a/devtools/client/netmonitor/test/browser_net_reload-markers.js
+++ b/devtools/client/netmonitor/test/browser_net_reload-markers.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if the empty-requests reload button works.
  */
 
 add_task(function* () {
-  let [,, monitor] = yield initNetMonitor(SINGLE_GET_URL);
+  let { monitor } = yield initNetMonitor(SINGLE_GET_URL);
   info("Starting test... ");
 
   let { document, EVENTS } = monitor.panelWin;
   let button = document.querySelector("#requests-menu-reload-notice-button");
   button.click();
 
   let markers = [];
 

--- a/devtools/client/netmonitor/test/browser_net_req-resp-bodies.js
+++ b/devtools/client/netmonitor/test/browser_net_req-resp-bodies.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Test if request and response body logging stays on after opening the console.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(JSON_LONG_URL);
+  let { tab, monitor } = yield initNetMonitor(JSON_LONG_URL);
   info("Starting test... ");
 
   let { L10N, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
 
   // Perform first batch of requests.

--- a/devtools/client/netmonitor/test/browser_net_resend.js
+++ b/devtools/client/netmonitor/test/browser_net_resend.js
@@ -7,17 +7,17 @@
  * Tests if resending a request works.
  */
 
 const ADD_QUERY = "t1=t2";
 const ADD_HEADER = "Test-header: true";
 const ADD_POSTDATA = "&t3=t4";
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(POST_DATA_URL);
+  let { tab, monitor } = yield initNetMonitor(POST_DATA_URL);
   info("Starting test... ");
 
   let { panelWin } = monitor;
   let { document, EVENTS, NetMonitorView } = panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
 

--- a/devtools/client/netmonitor/test/browser_net_security-details.js
+++ b/devtools/client/netmonitor/test/browser_net_security-details.js
@@ -3,17 +3,17 @@
    http://creativecommons.org/publicdomain/zero/1.0/ */
 "use strict";
 
 /**
  * Test that Security details tab contains the expected data.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CUSTOM_GET_URL);
+  let { tab, monitor } = yield initNetMonitor(CUSTOM_GET_URL);
   let { $, EVENTS, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu, NetworkDetails } = NetMonitorView;
   RequestsMenu.lazyUpdate = false;
 
   info("Performing a secure request.");
   const REQUESTS_URL = "https://example.com" + CORS_SJS_PATH;
   let wait = waitForNetworkEvents(monitor, 1);
   yield ContentTask.spawn(tab.linkedBrowser, REQUESTS_URL, function* (url) {

--- a/devtools/client/netmonitor/test/browser_net_security-error.js
+++ b/devtools/client/netmonitor/test/browser_net_security-error.js
@@ -3,17 +3,17 @@
    http://creativecommons.org/publicdomain/zero/1.0/ */
 "use strict";
 
 /**
  * Test that Security details tab shows an error message with broken connections.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CUSTOM_GET_URL);
+  let { tab, monitor } = yield initNetMonitor(CUSTOM_GET_URL);
   let { $, EVENTS, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu, NetworkDetails } = NetMonitorView;
   RequestsMenu.lazyUpdate = false;
 
   info("Requesting a resource that has a certificate problem.");
 
   let wait = waitForSecurityBrokenNetworkEvent();
   yield ContentTask.spawn(tab.linkedBrowser, {}, function* () {

--- a/devtools/client/netmonitor/test/browser_net_security-icon-click.js
+++ b/devtools/client/netmonitor/test/browser_net_security-icon-click.js
@@ -3,17 +3,17 @@
    http://creativecommons.org/publicdomain/zero/1.0/ */
 "use strict";
 
 /**
  * Test that clicking on the security indicator opens the security details tab.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CUSTOM_GET_URL);
+  let { tab, monitor } = yield initNetMonitor(CUSTOM_GET_URL);
   let { $, EVENTS, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu, NetworkDetails } = NetMonitorView;
   RequestsMenu.lazyUpdate = false;
 
   info("Requesting a resource over HTTPS.");
   yield performRequestAndWait("https://example.com" + CORS_SJS_PATH + "?request_2");
   yield performRequestAndWait("https://example.com" + CORS_SJS_PATH + "?request_1");
 

--- a/devtools/client/netmonitor/test/browser_net_security-redirect.js
+++ b/devtools/client/netmonitor/test/browser_net_security-redirect.js
@@ -4,17 +4,17 @@
 "use strict";
 
 /**
  * Test a http -> https redirect shows secure icon only for redirected https
  * request.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CUSTOM_GET_URL);
+  let { tab, monitor } = yield initNetMonitor(CUSTOM_GET_URL);
   let { $, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
   RequestsMenu.lazyUpdate = false;
 
   let wait = waitForNetworkEvents(monitor, 2);
   yield ContentTask.spawn(tab.linkedBrowser, HTTPS_REDIRECT_SJS, function* (url) {
     content.wrappedJSObject.performRequests(1, url);
   });

--- a/devtools/client/netmonitor/test/browser_net_security-state.js
+++ b/devtools/client/netmonitor/test/browser_net_security-state.js
@@ -11,17 +11,17 @@
 add_task(function* () {
   const EXPECTED_SECURITY_STATES = {
     "test1.example.com": "security-state-insecure",
     "example.com": "security-state-secure",
     "nocert.example.com": "security-state-broken",
     "localhost": "security-state-local",
   };
 
-  let [tab, , monitor] = yield initNetMonitor(CUSTOM_GET_URL);
+  let { tab, monitor } = yield initNetMonitor(CUSTOM_GET_URL);
   let { $, EVENTS, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
   RequestsMenu.lazyUpdate = false;
 
   yield performRequests();
 
   for (let item of RequestsMenu.items) {
     let domain = $(".requests-menu-domain", item.target).value;

--- a/devtools/client/netmonitor/test/browser_net_security-tab-deselect.js
+++ b/devtools/client/netmonitor/test/browser_net_security-tab-deselect.js
@@ -4,17 +4,17 @@
 "use strict";
 
 /**
  * Test that security details tab is no longer selected if an insecure request
  * is selected.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CUSTOM_GET_URL);
+  let { tab, monitor } = yield initNetMonitor(CUSTOM_GET_URL);
   let { EVENTS, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu, NetworkDetails } = NetMonitorView;
   RequestsMenu.lazyUpdate = false;
 
   info("Performing requests.");
   let wait = waitForNetworkEvents(monitor, 2);
   const REQUEST_URLS = [
     "https://example.com" + CORS_SJS_PATH,

--- a/devtools/client/netmonitor/test/browser_net_security-tab-visibility.js
+++ b/devtools/client/netmonitor/test/browser_net_security-tab-visibility.js
@@ -26,17 +26,17 @@ add_task(function* () {
       uri: "https://nocert.example.com",
       isBroken: true,
       visibleOnNewEvent: false,
       visibleOnSecurityInfo: true,
       visibleOnceComplete: true,
     }
   ];
 
-  let [tab, , monitor] = yield initNetMonitor(CUSTOM_GET_URL);
+  let { tab, monitor } = yield initNetMonitor(CUSTOM_GET_URL);
   let { $, EVENTS, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
   RequestsMenu.lazyUpdate = false;
 
   for (let testcase of TEST_DATA) {
     info("Testing Security tab visibility for " + testcase.desc);
     let onNewItem = monitor.panelWin.once(EVENTS.NETWORK_EVENT);
     let onSecurityInfo = monitor.panelWin.once(EVENTS.RECEIVED_SECURITY_INFO);

--- a/devtools/client/netmonitor/test/browser_net_security-warnings.js
+++ b/devtools/client/netmonitor/test/browser_net_security-warnings.js
@@ -11,17 +11,17 @@ const TEST_CASES = [
   {
     desc: "no warnings",
     uri: "https://example.com" + CORS_SJS_PATH,
     warnCipher: false,
   },
 ];
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CUSTOM_GET_URL);
+  let { tab, monitor } = yield initNetMonitor(CUSTOM_GET_URL);
   let { $, EVENTS, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu, NetworkDetails } = NetMonitorView;
   RequestsMenu.lazyUpdate = false;
 
   let cipher = $("#security-warning-cipher");
 
   for (let test of TEST_CASES) {
     info("Testing site with " + test.desc);

--- a/devtools/client/netmonitor/test/browser_net_send-beacon-other-tab.js
+++ b/devtools/client/netmonitor/test/browser_net_send-beacon-other-tab.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if beacons from other tabs are properly ignored.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(SIMPLE_URL);
+  let { tab, monitor } = yield initNetMonitor(SIMPLE_URL);
   let { RequestsMenu } = monitor.panelWin.NetMonitorView;
   RequestsMenu.lazyUpdate = false;
 
   let beaconTab = yield addTab(SEND_BEACON_URL);
   info("Beacon tab added successfully.");
 
   is(RequestsMenu.itemCount, 0, "The requests menu should be empty.");
 

--- a/devtools/client/netmonitor/test/browser_net_send-beacon.js
+++ b/devtools/client/netmonitor/test/browser_net_send-beacon.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if beacons are handled correctly.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(SEND_BEACON_URL);
+  let { tab, monitor } = yield initNetMonitor(SEND_BEACON_URL);
   let { RequestsMenu } = monitor.panelWin.NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
 
   is(RequestsMenu.itemCount, 0, "The requests menu should be empty.");
 
   let wait = waitForNetworkEvents(monitor, 1);
   yield ContentTask.spawn(tab.linkedBrowser, {}, function* () {

--- a/devtools/client/netmonitor/test/browser_net_service-worker-status.js
+++ b/devtools/client/netmonitor/test/browser_net_service-worker-status.js
@@ -8,17 +8,17 @@
  */
 
 // Service workers only work on https
 const URL = EXAMPLE_URL.replace("http:", "https:");
 
 const TEST_URL = URL + "service-workers/status-codes.html";
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(TEST_URL, null, true);
+  let { tab, monitor } = yield initNetMonitor(TEST_URL, null, true);
   info("Starting test... ");
 
   let { NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   const REQUEST_DATA = [
     {
       method: "GET",

--- a/devtools/client/netmonitor/test/browser_net_simple-init.js
+++ b/devtools/client/netmonitor/test/browser_net_simple-init.js
@@ -8,17 +8,17 @@
  */
 
 function test() {
   // These test suite functions are removed from the global scope inside a
   // cleanup function. However, we still need them.
   let gInfo = info;
   let gOk = ok;
 
-  initNetMonitor(SIMPLE_URL).then(([tab, , monitor]) => {
+  initNetMonitor(SIMPLE_URL).then(({ tab, monitor }) => {
     info("Starting test... ");
 
     is(tab.linkedBrowser.currentURI.spec, SIMPLE_URL,
       "The current tab's location is the correct one.");
 
     function checkIfInitialized(tag) {
       info(`Checking if initialization is ok (${tag}).`);
 

--- a/devtools/client/netmonitor/test/browser_net_simple-request-data.js
+++ b/devtools/client/netmonitor/test/browser_net_simple-request-data.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if requests render correct information in the menu UI.
  */
 
 function test() {
-  initNetMonitor(SIMPLE_SJS).then(([tab, , monitor]) => {
+  initNetMonitor(SIMPLE_SJS).then(({ tab, monitor }) => {
     info("Starting test... ");
 
     let { L10N, NetMonitorView } = monitor.panelWin;
     let { RequestsMenu } = NetMonitorView;
 
     RequestsMenu.lazyUpdate = false;
 
     waitForNetworkEvents(monitor, 1)

--- a/devtools/client/netmonitor/test/browser_net_simple-request-details.js
+++ b/devtools/client/netmonitor/test/browser_net_simple-request-details.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if requests render correct information in the details UI.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(SIMPLE_SJS);
+  let { tab, monitor } = yield initNetMonitor(SIMPLE_SJS);
   info("Starting test... ");
 
   let { document, EVENTS, L10N, Editor, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
   RequestsMenu.lazyUpdate = false;
 
   let wait = waitForNetworkEvents(monitor, 1);
   tab.linkedBrowser.reload();

--- a/devtools/client/netmonitor/test/browser_net_simple-request.js
+++ b/devtools/client/netmonitor/test/browser_net_simple-request.js
@@ -7,17 +7,17 @@
  * displayed in the Net panel. The following parts of the UI are
  * tested:
  * 1) Side panel visibility
  * 2) Side panel toggle button
  * 3) Empty user message visibility
  * 4) Number of requests displayed
  */
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(SIMPLE_URL);
+  let { tab, monitor } = yield initNetMonitor(SIMPLE_URL);
   info("Starting test... ");
 
   let { document, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
 
   is(document.querySelector("#details-pane-toggle").hasAttribute("disabled"), true,

--- a/devtools/client/netmonitor/test/browser_net_sort-01.js
+++ b/devtools/client/netmonitor/test/browser_net_sort-01.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Test if the sorting mechanism works correctly.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(STATUS_CODES_URL);
+  let { tab, monitor } = yield initNetMonitor(STATUS_CODES_URL);
   info("Starting test... ");
 
   let { $all, L10N, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
 
   let wait = waitForNetworkEvents(monitor, 5);

--- a/devtools/client/netmonitor/test/browser_net_sort-02.js
+++ b/devtools/client/netmonitor/test/browser_net_sort-02.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Test if sorting columns in the network table works correctly.
  */
 
 add_task(function* () {
-  let [,, monitor] = yield initNetMonitor(SORTING_URL);
+  let { monitor } = yield initNetMonitor(SORTING_URL);
   info("Starting test... ");
 
   // It seems that this test may be slow on debug builds. This could be because
   // of the heavy dom manipulation associated with sorting.
   requestLongerTimeout(2);
 
   let { $, $all, L10N, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;

--- a/devtools/client/netmonitor/test/browser_net_sort-03.js
+++ b/devtools/client/netmonitor/test/browser_net_sort-03.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Test if sorting columns in the network table works correctly with new requests.
  */
 
 add_task(function* () {
-  let [,, monitor] = yield initNetMonitor(SORTING_URL);
+  let { monitor } = yield initNetMonitor(SORTING_URL);
   info("Starting test... ");
 
   // It seems that this test may be slow on debug builds. This could be because
   // of the heavy dom manipulation associated with sorting.
   requestLongerTimeout(2);
 
   let { $, $all, L10N, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;

--- a/devtools/client/netmonitor/test/browser_net_statistics-01.js
+++ b/devtools/client/netmonitor/test/browser_net_statistics-01.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if the statistics view is populated correctly.
  */
 
 add_task(function* () {
-  let [,, monitor] = yield initNetMonitor(STATISTICS_URL);
+  let { monitor } = yield initNetMonitor(STATISTICS_URL);
   info("Starting test... ");
 
   let panel = monitor.panelWin;
   let { $, $all, EVENTS, NetMonitorView } = panel;
   is(NetMonitorView.currentFrontendMode, "network-inspector-view",
     "The initial frontend mode is correct.");
 
   is($("#primed-cache-chart").childNodes.length, 0,

--- a/devtools/client/netmonitor/test/browser_net_statistics-02.js
+++ b/devtools/client/netmonitor/test/browser_net_statistics-02.js
@@ -4,17 +4,17 @@
 "use strict";
 
 /**
  * Tests if the network inspector view is shown when the target navigates
  * away while in the statistics view.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(STATISTICS_URL);
+  let { tab, monitor } = yield initNetMonitor(STATISTICS_URL);
   info("Starting test... ");
 
   let panel = monitor.panelWin;
   let { EVENTS, NetMonitorView } = panel;
   is(NetMonitorView.currentFrontendMode, "network-inspector-view",
       "The initial frontend mode is correct.");
 
   let onChartDisplayed = Promise.all([

--- a/devtools/client/netmonitor/test/browser_net_statistics-03.js
+++ b/devtools/client/netmonitor/test/browser_net_statistics-03.js
@@ -4,17 +4,17 @@
 "use strict";
 
 /**
  * Test if the correct filtering predicates are used when filtering from
  * the performance analysis view.
  */
 
 add_task(function* () {
-  let [,, monitor] = yield initNetMonitor(FILTERING_URL);
+  let { monitor } = yield initNetMonitor(FILTERING_URL);
   info("Starting test... ");
 
   let panel = monitor.panelWin;
   let { $, EVENTS, NetMonitorView } = panel;
 
   EventUtils.sendMouseEvent({ type: "click" }, $("#requests-menu-filter-html-button"));
   EventUtils.sendMouseEvent({ type: "click" }, $("#requests-menu-filter-css-button"));
   EventUtils.sendMouseEvent({ type: "click" }, $("#requests-menu-filter-js-button"));

--- a/devtools/client/netmonitor/test/browser_net_status-codes.js
+++ b/devtools/client/netmonitor/test/browser_net_status-codes.js
@@ -3,17 +3,17 @@
    http://creativecommons.org/publicdomain/zero/1.0/ */
 "use strict";
 
 /**
  * Tests if requests display the correct status code and text in the UI.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(STATUS_CODES_URL);
+  let { tab, monitor } = yield initNetMonitor(STATUS_CODES_URL);
 
   info("Starting test... ");
 
   let { document, EVENTS, L10N, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu, NetworkDetails } = NetMonitorView;
   let requestItems = [];
 
   RequestsMenu.lazyUpdate = false;

--- a/devtools/client/netmonitor/test/browser_net_streaming-response.js
+++ b/devtools/client/netmonitor/test/browser_net_streaming-response.js
@@ -4,17 +4,17 @@
 "use strict";
 
 /**
  * Tests if reponses from streaming content types (MPEG-DASH, HLS) are
  * displayed as XML or plain text
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CUSTOM_GET_URL);
+  let { tab, monitor } = yield initNetMonitor(CUSTOM_GET_URL);
 
   info("Starting test... ");
   let { panelWin } = monitor;
   let { document, Editor, NetMonitorView } = panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   const REQUESTS = [
     [ "hls-m3u8", /^#EXTM3U/, Editor.modes.text ],

--- a/devtools/client/netmonitor/test/browser_net_throttle.js
+++ b/devtools/client/netmonitor/test/browser_net_throttle.js
@@ -8,17 +8,17 @@
 add_task(function* () {
   yield throttleTest(true);
   yield throttleTest(false);
 });
 
 function* throttleTest(actuallyThrottle) {
   requestLongerTimeout(2);
 
-  let [, , monitor] = yield initNetMonitor(SIMPLE_URL);
+  let { monitor } = yield initNetMonitor(SIMPLE_URL);
   const {ACTIVITY_TYPE, EVENTS, NetMonitorController, NetMonitorView} = monitor.panelWin;
 
   info("Starting test... (actuallyThrottle = " + actuallyThrottle + ")");
 
   // When throttling, must be smaller than the length of the content
   // of SIMPLE_URL in bytes.
   const size = actuallyThrottle ? 200 : 0;
 

--- a/devtools/client/netmonitor/test/browser_net_timeline_ticks.js
+++ b/devtools/client/netmonitor/test/browser_net_timeline_ticks.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if timeline correctly displays interval divisions.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(SIMPLE_URL);
+  let { tab, monitor } = yield initNetMonitor(SIMPLE_URL);
   info("Starting test... ");
 
   let { $, $all, L10N, NetMonitorView, NetMonitorController } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   // Disable transferred size column support for this test.
   // Without this, the waterfall only has enough room for one division, which
   // would remove most of the value of this test.

--- a/devtools/client/netmonitor/test/browser_net_timing-division.js
+++ b/devtools/client/netmonitor/test/browser_net_timing-division.js
@@ -3,17 +3,17 @@
 
 "use strict";
 
 /**
  * Tests if timing intervals are divided againts seconds when appropriate.
  */
 
 add_task(function* () {
-  let [tab, , monitor] = yield initNetMonitor(CUSTOM_GET_URL);
+  let { tab, monitor } = yield initNetMonitor(CUSTOM_GET_URL);
   info("Starting test... ");
 
   let { $all, NetMonitorView } = monitor.panelWin;
   let { RequestsMenu } = NetMonitorView;
 
   RequestsMenu.lazyUpdate = false;
 
   let wait = waitForNetworkEvents(monitor, 2);

--- a/devtools/client/netmonitor/test/head.js
+++ b/devtools/client/netmonitor/test/head.js
@@ -125,45 +125,46 @@ function initNetMonitor(aUrl, aWindow, a
       isnot([...target.activeConsole.getNetworkEvents()].length, 0,
          "Request to reconfigure the tab was recorded.");
       target.activeConsole.clearNetworkRequests();
     }
 
     let toolbox = yield gDevTools.showToolbox(target, "netmonitor");
     info("Network monitor pane shown successfully.");
 
-    let debuggee = tab.linkedBrowser.contentWindow.wrappedJSObject;
     let monitor = toolbox.getCurrentPanel();
-    return [tab, debuggee, monitor];
+    return {tab, monitor};
   });
 }
 
-function restartNetMonitor(aMonitor, aNewUrl) {
+function restartNetMonitor(monitor, newUrl) {
   info("Restarting the specified network monitor.");
 
-  let deferred = promise.defer();
-  let tab = aMonitor.target.tab;
-  let url = aNewUrl || tab.linkedBrowser.contentWindow.wrappedJSObject.location.href;
+  return Task.spawn(function* () {
+    let tab = monitor.target.tab;
+    let url = newUrl || tab.linkedBrowser.currentURI.spec;
 
-  aMonitor.once("destroyed", () => initNetMonitor(url).then(deferred.resolve));
-  removeTab(tab);
+    let onDestroyed = monitor.once("destroyed");
+    yield removeTab(tab);
+    yield onDestroyed;
 
-  return deferred.promise;
+    return initNetMonitor(url);
+  });
 }
 
-function teardown(aMonitor) {
+function teardown(monitor) {
   info("Destroying the specified network monitor.");
 
-  let deferred = promise.defer();
-  let tab = aMonitor.target.tab;
+  return Task.spawn(function* () {
+    let tab = monitor.target.tab;
 
-  aMonitor.once("destroyed", () => executeSoon(deferred.resolve));
-  removeTab(tab);
-
-  return deferred.promise;
+    let onDestroyed = monitor.once("destroyed");
+    yield removeTab(tab);
+    yield onDestroyed;
+  });
 }
 
 function waitForNetworkEvents(aMonitor, aGetRequests, aPostRequests = 0) {
   let deferred = promise.defer();
 
   let panel = aMonitor.panelWin;
   let events = panel.EVENTS;