Bug 1349363 - Use a centralized function to tell if e10s-multi is on. r=Felipe

MozReview-Commit-ID: JQJtCanIv3a

--HG--
extra : rebase_source : e459489211499ccc65b3b834ed0ec4e4d751994e

browser/base/content/tabbrowser.xml

@@ -4898,7 +4898,7 @@
                 tab.linkedBrowser &&
                 tab.linkedBrowser.isRemoteBrowser) {
               label += " - e10s";
-              if (Services.prefs.getIntPref("dom.ipc.processCount") > 1) {
+              if (Services.appinfo.maxWebProcessCount > 1) {
                 label += " (" + tab.linkedBrowser.frameLoader.tabParent.osPid + ")";
               }
             }

devtools/client/aboutdebugging/components/workers/multi-e10s-warning.js

@@ -20,7 +20,7 @@ loader.lazyRequireGetter(this, "DebuggerClient",
   "devtools/shared/client/main", true);
 
 const Strings = Services.strings.createBundle("chrome://devtools/locale/aboutdebugging.properties");
-const PROCESS_COUNT_PREF = "dom.ipc.processCount";
+const MULTI_OPT_OUT_PREF = "dom.ipc.multiOptOut";
 
 module.exports = createClass({
   displayName: "multiE10SWarning",
@@ -28,7 +28,9 @@ module.exports = createClass({
   onUpdatePreferenceClick() {
     let message = Strings.GetStringFromName("multiProcessWarningConfirmUpdate");
     if (window.confirm(message)) {
-      Services.prefs.setIntPref(PROCESS_COUNT_PREF, 1);
+      // Disable multi until at least the next experiment.
+      Services.prefs.setIntPref(MULTI_OPT_OUT_PREF,
+                                Services.appinfo.E10S_MULTI_EXPERIMENT);
       // Restart the browser.
       Services.startup.quit(Ci.nsIAppStartup.eAttemptQuit | Ci.nsIAppStartup.eRestart);
     }

devtools/client/aboutdebugging/components/workers/panel.js

@@ -75,7 +75,9 @@ module.exports = createClass({
   },
 
   updateMultiE10S() {
-    let processCount = Services.prefs.getIntPref(PROCESS_COUNT_PREF);
+    // We watch the pref but set the state based on
+    // nsIXULRuntime::maxWebProcessCount.
+    let processCount = Services.appinfo.maxWebProcessCount;
     this.setState({ processCount });
   },
 

dom/base/ProcessSelector.js

@@ -7,9 +7,6 @@ const { classes: Cc, interfaces: Ci, utils: Cu } = Components;
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 Cu.import('resource://gre/modules/Services.jsm');
 
-const BASE_PREF = "dom.ipc.processCount"
-const PREF_BRANCH = BASE_PREF + ".";
-
 // Fills up aProcesses until max and then selects randomly from the available
 // ones.
 function RandomSelector() {