Bug 1385090 - Pass Remote Pages instance from AboutNewTab on override r=mossop

MozReview-Commit-ID: 7oBsmIUpQXs

--HG--
extra : rebase_source : 820f50652c905aabe59ce7c3b248179608896157

browser/extensions/activity-stream/lib/ActivityStreamMessageChannel.jsm

@@ -126,11 +126,9 @@ this.ActivityStreamMessageChannel = class ActivityStreamMessageChannel {
    *                 between the main process and child pages
    */
   createChannel() {
-    //  RemotePageManager must be disabled for about:newtab, since only one can exist at once
-    if (this.pageURL === ABOUT_NEW_TAB_URL) {
-      AboutNewTab.override();
-    }
-    this.channel = new RemotePages(this.pageURL);
+    //  Receive AboutNewTab's Remote Pages instance, if it exists, on override
+    const channel = this.pageURL === ABOUT_NEW_TAB_URL && AboutNewTab.override(true);
+    this.channel = channel || new RemotePages(this.pageURL);
     this.channel.addMessageListener("RemotePage:Init", this.onNewTabInit);
     this.channel.addMessageListener("RemotePage:Load", this.onNewTabLoad);
     this.channel.addMessageListener("RemotePage:Unload", this.onNewTabUnload);
@@ -141,11 +139,16 @@ this.ActivityStreamMessageChannel = class ActivityStreamMessageChannel {
    * destroyChannel - Destroys the RemotePages channel
    */
   destroyChannel() {
-    this.channel.destroy();
-    this.channel = null;
+    this.channel.removeMessageListener("RemotePage:Init", this.onNewTabInit);
+    this.channel.removeMessageListener("RemotePage:Load", this.onNewTabLoad);
+    this.channel.removeMessageListener("RemotePage:Unload", this.onNewTabUnload);
+    this.channel.removeMessageListener(this.incomingMessageName, this.onMessage);
     if (this.pageURL === ABOUT_NEW_TAB_URL) {
-      AboutNewTab.reset();
+      AboutNewTab.reset(this.channel);
+    } else {
+      this.channel.destroy();
     }
+    this.channel = null;
   }
 
 /**

browser/modules/AboutNewTab.jsm

@@ -26,14 +26,14 @@ var AboutNewTab = {
 
   isOverridden: false,
 
-  init() {
+  init(pageListener) {
     if (this.isOverridden) {
       return;
     }
-    this.pageListener = new RemotePages("about:newtab");
-    this.pageListener.addMessageListener("NewTab:Customize", this.customize.bind(this));
+    this.pageListener = pageListener || new RemotePages("about:newtab");
+    this.pageListener.addMessageListener("NewTab:Customize", this.customize);
     this.pageListener.addMessageListener("NewTab:MaybeShowMigrateMessage",
-      this.maybeShowMigrateMessage.bind(this));
+      this.maybeShowMigrateMessage);
   },
 
   maybeShowMigrateMessage({ target }) {
@@ -56,13 +56,24 @@ var AboutNewTab = {
     }
   },
 
-  override() {
-    this.uninit();
+  override(shouldPassPageListener) {
     this.isOverridden = true;
+    const pageListener = this.pageListener;
+    if (!pageListener)
+      return null;
+    if (shouldPassPageListener) {
+      this.pageListener = null;
+      pageListener.removeMessageListener("NewTab:Customize", this.customize);
+      pageListener.removeMessageListener("NewTab:MaybeShowMigrateMessage",
+        this.maybeShowMigrateMessage);
+      return pageListener;
+    }
+    this.uninit();
+    return null;
   },
 
-  reset() {
+  reset(pageListener) {
     this.isOverridden = false;
-    this.init();
+    this.init(pageListener);
   }
 };

toolkit/modules/RemotePageManager.jsm

@@ -6,7 +6,7 @@
 
 this.EXPORTED_SYMBOLS = ["RemotePages", "RemotePageManager", "PageListener"];
 
-const { classes: Cc, interfaces: Ci, utils: Cu } = Components;
+const { classes: Cc, interfaces: Ci, utils: Cu, results: Cr } = Components;
 
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 Cu.import("resource://gre/modules/Services.jsm");
@@ -127,7 +127,14 @@ RemotePages.prototype = {
   // Sends a message to all known pages
   sendAsyncMessage(name, data = null) {
     for (let port of this.messagePorts.values()) {
-      port.sendAsyncMessage(name, data);
+      try {
+        port.sendAsyncMessage(name, data);
+      } catch (e) {
+        // Unless the port is in the process of unloading, something strange
+        // happened but allow other ports to receive the message
+        if (e.result !== Cr.NS_ERROR_NOT_INITIALIZED)
+          Cu.reportError(e);
+      }
     }
   },