Backed out changeset 7124641a168f (bug 1357486)

browser/app/profile/firefox.js

@@ -84,10 +84,6 @@ pref("extensions.geckoProfiler.getSymbolRules", "localBreakpad,remoteBreakpad");
 pref("extensions.webextensions.base-content-security-policy", "script-src 'self' https://* moz-extension: blob: filesystem: 'unsafe-eval' 'unsafe-inline'; object-src 'self' https://* moz-extension: blob: filesystem:;");
 pref("extensions.webextensions.default-content-security-policy", "script-src 'self'; object-src 'self';");
 
-#ifdef XP_WIN
-pref("extensions.webextensions.remote", true);
-#endif
-
 // Extensions that should not be flagged as legacy in about:addons
 pref("extensions.legacy.exceptions", "{972ce4c6-7e08-4474-a285-3208198ce6fd},testpilot@cliqz.com,@testpilot-containers,jid1-NeEaf3sAHdKHPA@jetpack,@activity-streams,pulse@mozilla.com,@testpilot-addon,@min-vid,tabcentertest1@mozilla.com,snoozetabs@mozilla.com,speaktome@mozilla.com,hoverpad@mozilla.com");
 

browser/components/extensions/test/browser/head.js

@@ -38,11 +38,11 @@ const {CustomizableUI} = Cu.import("resource:///modules/CustomizableUI.jsm", {})
 // browser-remote.ini. When running from browser-remote.ini, the tests are
 // copied to the sub-directory "test-oop-extensions", which we detect here, and
 // use to select our configuration.
-let remote = gTestPath.includes("test-oop-extensions");
-SpecialPowers.pushPrefEnv({set: [
-  ["extensions.webextensions.remote", remote],
-]});
-if (remote) {
+if (gTestPath.includes("test-oop-extensions")) {
+  SpecialPowers.pushPrefEnv({set: [
+    ["extensions.webextensions.remote", true],
+    ["layers.popups.compositing.enabled", true],
+  ]});
   // We don't want to reset this at the end of the test, so that we don't have
   // to spawn a new extension child process for each test unit.
   SpecialPowers.setIntPref("dom.ipc.keepProcessesAlive.extension", 1);

toolkit/components/extensions/Extension.jsm

@@ -752,6 +752,10 @@ this.Extension = class extends ExtensionData {
     if (this.remote && processCount !== 1) {
       throw new Error("Out-of-process WebExtensions are not supported with multiple child processes");
     }
+    if (this.remote && !Services.prefs.getBoolPref("layers.popups.compositing.enabled", false)) {
+      Cu.reportError(new Error("Remote extensions should not be enabled without also setting " +
+                               "the layers.popups.compositing.enabled preference to true"));
+    }
 
     // This is filled in the first time an extension child is created.
     this.parentMessageManager = null;

toolkit/components/extensions/test/mochitest/head.js

@@ -8,11 +8,11 @@ var {AppConstants} = SpecialPowers.Cu.import("resource://gre/modules/AppConstant
 // mochitest-remote.ini. When running from mochitest-remote.ini, the tests are
 // copied to the sub-directory "test-oop-extensions", which we detect here, and
 // use to select our configuration.
-let remote = location.pathname.includes("test-oop-extensions");
-SpecialPowers.pushPrefEnv({set: [
-  ["extensions.webextensions.remote", remote],
-]});
-if (remote) {
+if (location.pathname.includes("test-oop-extensions")) {
+  SpecialPowers.pushPrefEnv({set: [
+    ["extensions.webextensions.remote", true],
+    ["layers.popups.compositing.enabled", true],
+  ]});
   // We don't want to reset this at the end of the test, so that we don't have
   // to spawn a new extension child process for each test unit.
   SpecialPowers.setIntPref("dom.ipc.keepProcessesAlive.extension", 1);