--- a/devtools/client/scratchpad/test/head.js
+++ b/devtools/client/scratchpad/test/head.js
@@ -76,17 +76,17 @@ function openScratchpad(aReadyCallback, 
  *        are supported:
  *        - tabContent
  *          A string providing the html content of the tab.
  * @return Promise
  */
 function openTabAndScratchpad(aOptions = {}) {
   waitForExplicitFinish();
   // eslint-disable-next-line new-cap
-  return new promise(resolve => {
+  return new Promise(resolve => {
     gBrowser.selectedTab = BrowserTestUtils.addTab(gBrowser);
     const {selectedBrowser} = gBrowser;
     BrowserTestUtils.browserLoaded(selectedBrowser).then(function() {
       openScratchpad((win, sp) => resolve([win, sp]), aOptions);
     });
     gBrowser.loadURI("data:text/html;charset=utf8," + (aOptions.tabContent || ""));
   });
 }

--- a/devtools/client/shared/widgets/VariablesViewController.jsm
+++ b/devtools/client/shared/widgets/VariablesViewController.jsm
@@ -505,17 +505,17 @@ VariablesViewController.prototype = {
     });
   },
 
   _populateFromEntries: function(target, grip) {
     const objGrip = grip.obj;
     const objectClient = this._getObjectClient(objGrip);
 
     // eslint-disable-next-line new-cap
-    return new promise((resolve, reject) => {
+    return new Promise((resolve, reject) => {
       objectClient.enumEntries((response) => {
         if (response.error) {
           // Older server might not support the enumEntries method
           console.warn(response.error + ": " + response.message);
           resolve();
         } else {
           const sliceGrip = {
             type: "property-iterator",