new file mode 100644
--- /dev/null
+++ b/toolkit/components/extensions/test/xpcshell/head_telemetry.js
@@ -0,0 +1,34 @@
+/* -*- Mode: indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set sts=2 sw=2 et tw=80: */
+"use strict";
+
+/* exported IS_OOP, arraySum, clearHistograms, getSnapshots, promiseTelemetryRecorded */
+
+XPCOMUtils.defineLazyModuleGetter(this, "ContentTaskUtils",
+                                  "resource://testing-common/ContentTaskUtils.jsm");
+
+const IS_OOP = Services.prefs.getBoolPref("extensions.webextensions.remote");
+
+function arraySum(arr) {
+  return arr.reduce((a, b) => a + b, 0);
+}
+
+function clearHistograms() {
+  Services.telemetry.snapshotSubsessionHistograms(true);
+}
+
+function getSnapshots(process) {
+  return Services.telemetry.snapshotSubsessionHistograms()[process];
+}
+
+// There is no good way to make sure that the parent received the histogram
+// entries from the extension and content processes.
+// Let's stick to the ugly, spinning the event loop until we have a good
+// approach (Bug 1357509).
+function promiseTelemetryRecorded(id, process, expectedCount) {
+  let condition = () => {
+    let snapshot = Services.telemetry.snapshotSubsessionHistograms()[process][id];
+    return snapshot && arraySum(snapshot.counts) >= expectedCount;
+  };
+  return ContentTaskUtils.waitForCondition(condition);
+}

--- a/toolkit/components/extensions/test/xpcshell/test_ext_extension_content_telemetry.js
+++ b/toolkit/components/extensions/test/xpcshell/test_ext_extension_content_telemetry.js
@@ -36,38 +36,41 @@ add_task(async function test_telemetry()
       }],
     },
 
     files: {
       "content_script.js": contentScript,
     },
   });
 
-  let histogram = Services.telemetry.getHistogramById(HISTOGRAM);
-  histogram.clear();
-  equal(histogram.snapshot().sum, 0,
-        `No data recorded for histogram: ${HISTOGRAM}.`);
+  clearHistograms();
+
+  let process = IS_OOP ? "content" : "parent";
+  ok(!(HISTOGRAM in getSnapshots(process)), `No data recorded for histogram: ${HISTOGRAM}.`);
 
   await extension1.startup();
-  equal(histogram.snapshot().sum, 0,
-        `No data recorded for histogram after startup: ${HISTOGRAM}.`);
+  ok(!(HISTOGRAM in getSnapshots(process)),
+     `No data recorded for histogram after startup: ${HISTOGRAM}.`);
 
   let contentPage = await ExtensionTestUtils.loadContentPage(`${BASE_URL}/file_sample.html`);
   await extension1.awaitMessage("content-script-run");
-  let histogramSum = histogram.snapshot().sum;
-  ok(histogramSum > 0,
-     `Data recorded for first extension for histogram: ${HISTOGRAM}.`);
+  await promiseTelemetryRecorded(HISTOGRAM, process, 1);
+
+  equal(arraySum(getSnapshots(process)[HISTOGRAM].counts), 1,
+        `Data recorded for histogram: ${HISTOGRAM}.`);
 
   await contentPage.close();
   await extension1.unload();
 
   await extension2.startup();
-  equal(histogram.snapshot().sum, histogramSum,
+  equal(arraySum(getSnapshots(process)[HISTOGRAM].counts), 1,
         `No data recorded for histogram after startup: ${HISTOGRAM}.`);
 
   contentPage = await ExtensionTestUtils.loadContentPage(`${BASE_URL}/file_sample.html`);
   await extension2.awaitMessage("content-script-run");
-  ok(histogram.snapshot().sum > histogramSum,
-     `Data recorded for second extension for histogram: ${HISTOGRAM}.`);
+  await promiseTelemetryRecorded(HISTOGRAM, process, 2);
+
+  equal(arraySum(getSnapshots(process)[HISTOGRAM].counts), 2,
+        `Data recorded for histogram: ${HISTOGRAM}.`);
 
   await contentPage.close();
   await extension2.unload();
 });

--- a/toolkit/components/extensions/test/xpcshell/test_ext_storage_telemetry.js
+++ b/toolkit/components/extensions/test/xpcshell/test_ext_storage_telemetry.js
@@ -1,20 +1,16 @@
 /* -*- Mode: indent-tabs-mode: nil; js-indent-level: 2 -*- */
 /* vim: set sts=2 sw=2 et tw=80: */
 "use strict";
 
 const HISTOGRAM_IDS = [
   "WEBEXT_STORAGE_LOCAL_SET_MS", "WEBEXT_STORAGE_LOCAL_GET_MS",
 ];
 
-function arraySum(arr) {
-  return arr.reduce((a, b) => a + b, 0);
-}
-
 add_task(async function test_telemetry_background() {
   const server = createHttpServer();
   server.registerDirectory("/data/", do_get_file("data"));
 
   const BASE_URL = `http://localhost:${server.identity.primaryPort}/data`;
 
   async function contentScript() {
     await browser.storage.local.set({a: "b"});
@@ -44,51 +40,65 @@ add_task(async function test_telemetry_b
     files: {
       "content_script.js": contentScript,
     },
   };
 
   let extension1 = ExtensionTestUtils.loadExtension(extInfo);
   let extension2 = ExtensionTestUtils.loadExtension(extInfo);
 
-  // Initialize and clear histograms.
-  let histograms = {};
+  clearHistograms();
+
+  let process = IS_OOP ? "extension" : "parent";
+  let snapshots = getSnapshots(process);
   for (let id of HISTOGRAM_IDS) {
-    histograms[id] = Services.telemetry.getHistogramById(id);
-    histograms[id].clear();
-    equal(arraySum(histograms[id].snapshot().counts), 0,
-          `No data recorded for histogram: ${id}.`);
+    ok(!(id in snapshots), `No data recorded for histogram: ${id}.`);
   }
 
   await extension1.startup();
   await extension1.awaitMessage("backgroundDone");
+  for (let id of HISTOGRAM_IDS) {
+    await promiseTelemetryRecorded(id, process, 1);
+  }
 
   // Telemetry from extension1's background page should be recorded.
-  for (let id in histograms) {
-    equal(arraySum(histograms[id].snapshot().counts), 1,
+  snapshots = getSnapshots(process);
+  for (let id of HISTOGRAM_IDS) {
+    equal(arraySum(snapshots[id].counts), 1,
           `Data recorded for histogram: ${id}.`);
   }
 
   await extension2.startup();
   await extension2.awaitMessage("backgroundDone");
+  for (let id of HISTOGRAM_IDS) {
+    await promiseTelemetryRecorded(id, process, 2);
+  }
 
   // Telemetry from extension2's background page should be recorded.
-  for (let id in histograms) {
-    equal(arraySum(histograms[id].snapshot().counts), 2,
+  snapshots = getSnapshots(process);
+  for (let id of HISTOGRAM_IDS) {
+    equal(arraySum(snapshots[id].counts), 2,
           `Additional data recorded for histogram: ${id}.`);
   }
 
   await extension2.unload();
 
   // Run a content script.
+  process = IS_OOP ? "content" : "parent";
+  let expectedCount = IS_OOP ? 1 : 3;
   let contentScriptPromise = extension1.awaitMessage("contentDone");
   let contentPage = await ExtensionTestUtils.loadContentPage(`${BASE_URL}/file_sample.html`);
   await contentScriptPromise;
   await contentPage.close();
 
+  for (let id of HISTOGRAM_IDS) {
+    await promiseTelemetryRecorded(id, process, expectedCount);
+  }
+
   // Telemetry from extension1's content script should be recorded.
-  for (let id in histograms) {
-    equal(arraySum(histograms[id].snapshot().counts), 3,
+  snapshots = getSnapshots(process);
+  for (let id of HISTOGRAM_IDS) {
+    equal(arraySum(snapshots[id].counts), expectedCount,
           `Data recorded in content script for histogram: ${id}.`);
   }
 
   await extension1.unload();
 });

--- a/toolkit/components/extensions/test/xpcshell/xpcshell-common.ini
+++ b/toolkit/components/extensions/test/xpcshell/xpcshell-common.ini
@@ -8,30 +8,33 @@
 [test_ext_background_global_history.js]
 skip-if = os == "android" # Android does not use Places for history.
 [test_ext_background_private_browsing.js]
 [test_ext_background_runtime_connect_params.js]
 [test_ext_background_sub_windows.js]
 [test_ext_background_telemetry.js]
 [test_ext_background_window_properties.js]
 skip-if = os == "android"
+[test_ext_browserSettings.js]
 [test_ext_contextual_identities.js]
 skip-if = os == "android" # Containers are not exposed to android.
 [test_ext_debugging_utils.js]
 [test_ext_downloads.js]
 [test_ext_downloads_download.js]
 skip-if = os == "android"
 [test_ext_downloads_misc.js]
 skip-if = os == "android" || (os=='linux' && bits==32) # linux32: bug 1324870
 [test_ext_downloads_search.js]
 skip-if = os == "android"
 [test_ext_experiments.js]
 [test_ext_extension.js]
 [test_ext_extensionPreferencesManager.js]
 [test_ext_extensionSettingsStore.js]
+[test_ext_extension_content_telemetry.js]
+skip-if = os == "android" # checking for telemetry needs to be updated: 1384923
 [test_ext_extension_startup_telemetry.js]
 [test_ext_idle.js]
 [test_ext_legacy_extension_context.js]
 [test_ext_legacy_extension_embedding.js]
 [test_ext_localStorage.js]
 [test_ext_management.js]
 [test_ext_management_uninstall_self.js]
 [test_ext_onmessage_removelistener.js]
@@ -51,12 +54,14 @@ skip-if = true # This test no longer tes
 [test_ext_simple.js]
 [test_ext_startup_cache.js]
 [test_ext_storage.js]
 [test_ext_storage_sync.js]
 head = head.js head_sync.js
 skip-if = os == "android"
 [test_ext_storage_sync_crypto.js]
 skip-if = os == "android"
+[test_ext_storage_telemetry.js]
+skip-if = os == "android" # checking for telemetry needs to be updated: 1384923
 [test_ext_topSites.js]
 skip-if = os == "android"
 [test_native_messaging.js]
 skip-if = os == "android"

--- a/toolkit/components/extensions/test/xpcshell/xpcshell-remote.ini
+++ b/toolkit/components/extensions/test/xpcshell/xpcshell-remote.ini
@@ -1,10 +1,10 @@
 [DEFAULT]
-head = head.js head_remote.js head_e10s.js
+head = head.js head_remote.js head_e10s.js head_telemetry.js
 tail =
 firefox-appdir = browser
 skip-if = appname == "thunderbird" || os == "android"
 dupe-manifest =
 support-files =
   data/**
   xpcshell-content.ini
 tags = webextensions remote-webextensions

--- a/toolkit/components/extensions/test/xpcshell/xpcshell.ini
+++ b/toolkit/components/extensions/test/xpcshell/xpcshell.ini
@@ -1,10 +1,10 @@
 [DEFAULT]
-head = head.js
+head = head.js head_telemetry.js
 firefox-appdir = browser
 skip-if = appname == "thunderbird"
 dupe-manifest =
 support-files =
   data/**
   head_sync.js
   xpcshell-content.ini
 tags = webextensions in-process-webextensions