Bug 1394580 - 1. Only load AsyncPrefs for Fennec; r=esawin

Move AsyncPrefs initialization to inside browser.js to only load it for
Fennec. Also, delay initialization until later in startup.

MozReview-Commit-ID: 7gLaXA5UJud

--HG--
extra : rebase_source : c71edca4a13f3de785e06f2e0a249ff80fd8c1d4

mobile/android/chrome/content/browser.js

@@ -22,6 +22,9 @@ if (AppConstants.ACCESSIBILITY) {
                                     "resource://gre/modules/accessibility/AccessFu.jsm");
 }
 
+XPCOMUtils.defineLazyModuleGetter(this, "AsyncPrefs",
+                                  "resource://gre/modules/AsyncPrefs.jsm");
+
 XPCOMUtils.defineLazyModuleGetter(this, "Manifests",
                                   "resource://gre/modules/Manifest.jsm");
 
@@ -529,6 +532,9 @@ var BrowserApp = {
       InitLater(() => Services.obs.notifyObservers(window, "browser-delayed-startup-finished"));
       InitLater(() => GlobalEventDispatcher.sendRequest({ type: "Gecko:DelayedStartup" }));
 
+      // AsyncPrefs is needed for reader mode.
+      InitLater(() => AsyncPrefs.init());
+
       if (!AppConstants.RELEASE_OR_BETA) {
         InitLater(() => WebcompatReporter.init());
       }

mobile/android/components/geckoview/GeckoViewPrompt.js

@@ -7,9 +7,6 @@ const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
 Cu.import("resource://gre/modules/Services.jsm");
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 
-XPCOMUtils.defineLazyModuleGetter(this, "AsyncPrefs",
-                                  "resource://gre/modules/AsyncPrefs.jsm");
-
 XPCOMUtils.defineLazyModuleGetter(this, "ContentPrefServiceParent",
                                   "resource://gre/modules/ContentPrefServiceParent.jsm");
 
@@ -42,8 +39,6 @@ PromptFactory.prototype = {
       case "profile-after-change": {
         // ContentPrefServiceParent is needed for e10s file picker.
         ContentPrefServiceParent.init();
-        // AsyncPrefs is needed for reader mode.
-        AsyncPrefs.init();
         Services.mm.addMessageListener("GeckoView:Prompt", this);
         break;
       }