From c25109716925537e6b5fa4ef5cae237a35a9cb1d Mon Sep 17 00:00:00 2001
From: Tim Chien <timdream@gmail.com>
Date: Mon, 28 Sep 2015 09:27:49 -0700
Subject: [PATCH] Bug 1160923 - [B2G] Waiting for explicit mozContentEvent
 before sending out mozChromeEvents, r=vingtetun, f=ochaumeau

---
 b2g/chrome/content/devtools/hud.js            |  11 +-
 b2g/chrome/content/shell.js                   | 111 +++++++++++-------
 b2g/components/SystemAppProxy.jsm             |  53 ++++++++-
 .../test/mochitest/systemapp_helper.js        |  48 ++++++--
 .../NetworkPreparationChromeScript.js         |   3 -
 testing/mochitest/b2g_start_script.js         |   3 +
 6 files changed, 157 insertions(+), 72 deletions(-)

diff --git a/b2g/chrome/content/devtools/hud.js b/b2g/chrome/content/devtools/hud.js
index 3836e7e75547..6ca5ee297d39 100644
--- a/b2g/chrome/content/devtools/hud.js
+++ b/b2g/chrome/content/devtools/hud.js
@@ -190,7 +190,7 @@ var developerHUD = {
  * metrics, and how to notify the front-end when metrics have changed.
  */
 function Target(frame, actor) {
-  this._frame = frame;
+  this.frame = frame;
   this.actor = actor;
   this.metrics = new Map();
   this._appName = null;
@@ -198,15 +198,8 @@ function Target(frame, actor) {
 
 Target.prototype = {
 
-  get frame() {
-    let frame = this._frame;
-    let systemapp = document.querySelector('#systemapp');
-
-    return (frame === systemapp ? getContentWindow() : frame);
-  },
-
   get manifest() {
-    return this._frame.appManifestURL;
+    return this.frame.appManifestURL;
   },
 
   get appName() {
diff --git a/b2g/chrome/content/shell.js b/b2g/chrome/content/shell.js
index e4c6fdec951d..7d39f4939bb9 100644
--- a/b2g/chrome/content/shell.js
+++ b/b2g/chrome/content/shell.js
@@ -82,10 +82,6 @@ XPCOMUtils.defineLazyModuleGetter(this, "SafeMode",
 
 window.performance.measure('gecko-shell-jsm-loaded', 'gecko-shell-loadstart');
 
-function getContentWindow() {
-  return shell.contentBrowser.contentWindow;
-}
-
 function debug(str) {
   dump(' -*- Shell.js: ' + str + '\n');
 }
@@ -388,7 +384,7 @@ var shell = {
     CaptivePortalLoginHelper.init();
 
     this.contentBrowser.src = homeURL;
-    this.isHomeLoaded = false;
+    this._isEventListenerReady = false;
 
     window.performance.mark('gecko-shell-system-frame-set');
 
@@ -480,6 +476,13 @@ var shell = {
           this.contentBrowser.setVisible(true);
         }
         break;
+      case 'load':
+        if (content.document.location == 'about:blank') {
+          return;
+        }
+        content.removeEventListener('load', this, true);
+        this.notifyContentWindowLoaded();
+        break;
       case 'mozbrowserloadstart':
         if (content.document.location == 'about:blank') {
           this.contentBrowser.addEventListener('mozbrowserlocationchange', this, true);
@@ -586,9 +589,12 @@ var shell = {
         break;
       case 'MozAfterPaint':
         window.removeEventListener('MozAfterPaint', this);
-        this.sendChromeEvent({
+        // This event should be sent before System app returns with
+        // system-message-listener-ready mozContentEvent, because it's on
+        // the critical launch path of the app.
+        SystemAppProxy._sendCustomEvent('mozChromeEvent', {
           type: 'system-first-paint'
-        });
+        }, /* noPending */ true);
         break;
       case 'unload':
         this.stop();
@@ -610,6 +616,14 @@ var shell = {
 
   // Send an event to a specific window, document or element.
   sendEvent: function shell_sendEvent(target, type, details) {
+    if (target === this.contentBrowser) {
+      // We must ask SystemAppProxy to send the event in this case so
+      // that event would be dispatched from frame.contentWindow instead of
+      // on the System app frame.
+      SystemAppProxy._sendCustomEvent(type, details);
+      return;
+    }
+
     let doc = target.document || target.ownerDocument || target;
     let event = doc.createEvent('CustomEvent');
     event.initCustomEvent(type, true, true, details ? details : {});
@@ -617,21 +631,10 @@ var shell = {
   },
 
   sendCustomEvent: function shell_sendCustomEvent(type, details) {
-    let target = getContentWindow();
-    let payload = details ? Cu.cloneInto(details, target) : {};
-    this.sendEvent(target, type, payload);
+    SystemAppProxy._sendCustomEvent(type, details);
   },
 
   sendChromeEvent: function shell_sendChromeEvent(details) {
-    if (!this.isHomeLoaded) {
-      if (!('pendingChromeEvents' in this)) {
-        this.pendingChromeEvents = [];
-      }
-
-      this.pendingChromeEvents.push(details);
-      return;
-    }
-
     this.sendCustomEvent("mozChromeEvent", details);
   },
 
@@ -672,6 +675,7 @@ var shell = {
     this.contentBrowser.removeEventListener('mozbrowserlocationchange', this, true);
 
     let content = this.contentBrowser.contentWindow;
+    content.addEventListener('load', this, true);
 
     this.reportCrash(true);
 
@@ -685,28 +689,7 @@ var shell = {
     Cu.import('resource://gre/modules/OperatorApps.jsm');
 #endif
 
-    content.addEventListener('load', function shell_homeLoaded() {
-      content.removeEventListener('load', shell_homeLoaded);
-      shell.isHomeLoaded = true;
-
-      if (Services.prefs.getBoolPref('b2g.orientation.animate')) {
-        Cu.import('resource://gre/modules/OrientationChangeHandler.jsm');
-      }
-
-#ifdef MOZ_WIDGET_GONK
-      libcutils.property_set('sys.boot_completed', '1');
-#endif
-
-      Services.obs.notifyObservers(null, "browser-ui-startup-complete", "");
-
-      SystemAppProxy.setIsReady();
-      if ('pendingChromeEvents' in shell) {
-        shell.pendingChromeEvents.forEach((shell.sendChromeEvent).bind(shell));
-      }
-      delete shell.pendingChromeEvents;
-    });
-
-    shell.handleCmdLine();
+    this.handleCmdLine();
   },
 
   handleCmdLine: function shell_handleCmdLine() {
@@ -727,6 +710,38 @@ var shell = {
     }
 #endif
   },
+
+  // This gets called when window.onload fires on the System app content window,
+  // which means things in <html> are parsed and statically referenced <script>s
+  // and <script defer>s are loaded and run.
+  notifyContentWindowLoaded: function shell_notifyContentWindowLoaded() {
+#ifdef MOZ_WIDGET_GONK
+    libcutils.property_set('sys.boot_completed', '1');
+#endif
+
+    // This will cause Gonk Widget to remove boot animation from the screen
+    // and reveals the page.
+    Services.obs.notifyObservers(null, "browser-ui-startup-complete", "");
+
+    SystemAppProxy.setIsLoaded();
+  },
+
+  // This gets called when the content sends us system-message-listener-ready
+  // mozContentEvent, OR when an observer message tell us we should consider
+  // the content as ready.
+  notifyEventListenerReady: function shell_notifyEventListenerReady() {
+    if (this._isEventListenerReady) {
+      Cu.reportError('shell.js: SystemApp has already been declared as being ready.');
+      return;
+    }
+    this._isEventListenerReady = true;
+
+    if (Services.prefs.getBoolPref('b2g.orientation.animate')) {
+      Cu.import('resource://gre/modules/OrientationChangeHandler.jsm');
+    }
+
+    SystemAppProxy.setIsReady();
+  }
 };
 
 Services.obs.addObserver(function onFullscreenOriginChange(subject, topic, data) {
@@ -734,11 +749,13 @@ Services.obs.addObserver(function onFullscreenOriginChange(subject, topic, data)
                           fullscreenorigin: data });
 }, "fullscreen-origin-change", false);
 
-DOMApplicationRegistry.registryStarted.then(function () {
-  shell.sendChromeEvent({ type: 'webapps-registry-start' });
-});
 DOMApplicationRegistry.registryReady.then(function () {
-  shell.sendChromeEvent({ type: 'webapps-registry-ready' });
+  // This event should be sent before System app returns with
+  // system-message-listener-ready mozContentEvent, because it's on
+  // the critical launch path of the app.
+  SystemAppProxy._sendCustomEvent('mozChromeEvent', {
+    type: 'webapps-registry-ready'
+  }, /* noPending */ true);
 });
 
 Services.obs.addObserver(function onBluetoothVolumeChange(subject, topic, data) {
@@ -752,6 +769,10 @@ Services.obs.addObserver(function(subject, topic, data) {
   shell.sendCustomEvent('mozmemorypressure');
 }, 'memory-pressure', false);
 
+Services.obs.addObserver(function(subject, topic, data) {
+  shell.notifyEventListenerReady();
+}, 'system-message-listener-ready', false);
+
 var permissionMap = new Map([
   ['unknown', Services.perms.UNKNOWN_ACTION],
   ['allow', Services.perms.ALLOW_ACTION],
diff --git a/b2g/components/SystemAppProxy.jsm b/b2g/components/SystemAppProxy.jsm
index 29266773f936..8eb557e2b9a6 100644
--- a/b2g/components/SystemAppProxy.jsm
+++ b/b2g/components/SystemAppProxy.jsm
@@ -13,8 +13,10 @@ this.EXPORTED_SYMBOLS = ['SystemAppProxy'];
 
 var SystemAppProxy = {
   _frame: null,
+  _isLoaded: false,
   _isReady: false,
-  _pendingEvents: [],
+  _pendingLoadedEvents: [],
+  _pendingReadyEvents: [],
   _pendingListeners: [],
 
   // To call when a new system app iframe is created
@@ -34,18 +36,38 @@ var SystemAppProxy = {
     return this._frame;
   },
 
+  // To call when the load event of the System app document is triggered.
+  // i.e. everything that is not lazily loaded are run and done.
+  setIsLoaded: function () {
+    if (this._isLoaded) {
+      Cu.reportError('SystemApp has already been declared as being loaded.');
+    }
+    this._isLoaded = true;
+
+    // Dispatch all events being queued while the system app was still loading
+    this._pendingLoadedEvents
+        .forEach(([type, details]) =>
+                 this._sendCustomEvent(type, details, true));
+    this._pendingLoadedEvents = [];
+  },
+
   // To call when it is ready to receive events
+  // i.e. when system-message-listener-ready mozContentEvent is sent.
   setIsReady: function () {
+    if (!this._isLoaded) {
+      Cu.reportError('SystemApp.setIsLoaded() should be called before setIsReady().');
+    }
+
     if (this._isReady) {
       Cu.reportError('SystemApp has already been declared as being ready.');
     }
     this._isReady = true;
 
-    // Dispatch all events being queued while the system app was still loading
-    this._pendingEvents
+    // Dispatch all events being queued while the system app was still not ready
+    this._pendingReadyEvents
         .forEach(([type, details]) =>
                  this._sendCustomEvent(type, details));
-    this._pendingEvents = [];
+    this._pendingReadyEvents = [];
   },
 
   /*
@@ -62,6 +84,9 @@ var SystemAppProxy = {
    *   @param details   The event details.
    *   @param noPending Set to true to emit this event even before the system
    *                    app is ready.
+   *                    Event is always pending if the app is not loaded yet.
+   *
+   *   @returns event?  Dispatched event, or null if the event is pending.
    */
   _sendCustomEvent: function systemApp_sendCustomEvent(type,
                                                        details,
@@ -69,10 +94,22 @@ var SystemAppProxy = {
                                                        target) {
     let content = this._frame ? this._frame.contentWindow : null;
 
+    // If the system app isn't loaded yet,
+    // queue events until someone calls setIsLoaded
+    if (!content || !this._isLoaded) {
+      if (noPending) {
+        this._pendingLoadedEvents.push([type, details]);
+      } else {
+        this._pendingReadyEvents.push([type, details]);
+      }
+
+      return null;
+    }
+
     // If the system app isn't ready yet,
     // queue events until someone calls setIsReady
-    if (!content || (!this._isReady && !noPending)) {
-      this._pendingEvents.push([type, details]);
+    if (!this._isReady && !noPending) {
+      this._pendingReadyEvents.push([type, details]);
       return null;
     }
 
@@ -87,6 +124,10 @@ var SystemAppProxy = {
       payload = details ? Cu.cloneInto(details, content) : {};
     }
 
+    if ((target || content) === this._frame.contentWindow) {
+      dump('XXX FIXME : Dispatch a ' + type + ': ' + details.type + "\n");
+    }
+
     event.initCustomEvent(type, true, false, payload);
     (target || content).dispatchEvent(event);
 
diff --git a/b2g/components/test/mochitest/systemapp_helper.js b/b2g/components/test/mochitest/systemapp_helper.js
index 32d247d1eb84..5a901b48416f 100644
--- a/b2g/components/test/mochitest/systemapp_helper.js
+++ b/b2g/components/test/mochitest/systemapp_helper.js
@@ -27,10 +27,11 @@ function next() {
 // Listen for events received by the system app document
 // to ensure that we receive all of them, in an expected order and time
 var isLoaded = false;
+var isReady = false;
 var n = 0;
 function listener(event) {
   if (!isLoaded) {
-    assert.ok(false, "Received event before the iframe is ready");
+    assert.ok(false, "Received event before the iframe is loaded");
     return;
   }
   n++;
@@ -41,16 +42,34 @@ function listener(event) {
     assert.equal(event.type, "custom");
     assert.equal(event.detail.name, "second");
 
-    next(); // call checkEventDispatching
+    next(); // call checkEventPendingBeforeLoad
   } else if (n == 3) {
+    if (!isReady) {
+      assert.ok(false, "Received event before the iframe is loaded");
+      return;
+    }
+
     assert.equal(event.type, "custom");
     assert.equal(event.detail.name, "third");
   } else if (n == 4) {
+    if (!isReady) {
+      assert.ok(false, "Received event before the iframe is loaded");
+      return;
+    }
+
     assert.equal(event.type, "mozChromeEvent");
     assert.equal(event.detail.name, "fourth");
+
+    next(); // call checkEventDispatching
   } else if (n == 5) {
     assert.equal(event.type, "custom");
     assert.equal(event.detail.name, "fifth");
+  } else if (n === 6) {
+    assert.equal(event.type, "mozChromeEvent");
+    assert.equal(event.detail.name, "sixth");
+  } else if (n === 7) {
+    assert.equal(event.type, "custom");
+    assert.equal(event.detail.name, "seventh");
     assert.equal(event.target, customEventTarget);
 
     next(); // call checkEventListening();
@@ -72,8 +91,8 @@ var steps = [
 
   function earlyEvents() {
     // Immediately try to send events
-    SystemAppProxy.dispatchEvent({ name: "first" });
-    SystemAppProxy._sendCustomEvent("custom", { name: "second" });
+    SystemAppProxy._sendCustomEvent("mozChromeEvent", { name: "first" }, true);
+    SystemAppProxy._sendCustomEvent("custom", { name: "second" }, true);
     next();
   },
 
@@ -110,7 +129,7 @@ var steps = [
       // Declare that the iframe is now loaded.
       // That should dispatch early events
       isLoaded = true;
-      SystemAppProxy.setIsReady();
+      SystemAppProxy.setIsLoaded();
       assert.ok(true, "Frame declared as loaded");
 
       let gotFrame = SystemAppProxy.getFrame();
@@ -123,13 +142,24 @@ var steps = [
     frame.setAttribute("src", "data:text/html,system app");
   },
 
+  function checkEventPendingBeforeLoad() {
+    // Frame is loaded but not ready,
+    // these events should queue before the System app is ready.
+    SystemAppProxy._sendCustomEvent("custom", { name: "third" });
+    SystemAppProxy.dispatchEvent({ name: "fourth" });
+
+    isReady = true;
+    SystemAppProxy.setIsReady();
+    // Once this 4th event is received, we will run checkEventDispatching
+  },
+
   function checkEventDispatching() {
     // Send events after the iframe is ready,
     // they should be dispatched right away
-    SystemAppProxy._sendCustomEvent("custom", { name: "third" });
-    SystemAppProxy.dispatchEvent({ name: "fourth" });
-    SystemAppProxy._sendCustomEvent("custom", { name: "fifth" }, false, customEventTarget);
-    // Once this 5th event is received, we will run checkEventListening
+    SystemAppProxy._sendCustomEvent("custom", { name: "fifth" });
+    SystemAppProxy.dispatchEvent({ name: "sixth" });
+    SystemAppProxy._sendCustomEvent("custom", { name: "seventh" }, false, customEventTarget);
+    // Once this 7th event is received, we will run checkEventListening
   },
 
   function checkEventListening() {
diff --git a/dom/media/tests/mochitest/NetworkPreparationChromeScript.js b/dom/media/tests/mochitest/NetworkPreparationChromeScript.js
index 4614334f5fc1..1de778778c6b 100644
--- a/dom/media/tests/mochitest/NetworkPreparationChromeScript.js
+++ b/dom/media/tests/mochitest/NetworkPreparationChromeScript.js
@@ -38,9 +38,6 @@ function disableRadio() {
 }
 
 addMessageListener('prepare-network', function(message) {
-  //RIL DOM events will be pending until RIL receiveing system-message-listener-ready event.
-  Services.obs.notifyObservers(null, 'system-message-listener-ready', null);
-
   connection.addEventListener('datachange', function onDataChange() {
     if (connection.data.connected) {
       connection.removeEventListener('datachange', onDataChange);
diff --git a/testing/mochitest/b2g_start_script.js b/testing/mochitest/b2g_start_script.js
index f48922800a8d..43de589ef980 100644
--- a/testing/mochitest/b2g_start_script.js
+++ b/testing/mochitest/b2g_start_script.js
@@ -32,6 +32,9 @@ if (cm) {
 var SECURITY_PREF = "security.turn_off_all_security_so_that_viruses_can_take_over_this_computer";
 Components.utils.import("resource://gre/modules/Services.jsm");
 Services.prefs.setBoolPref(SECURITY_PREF, true);
+// RIL DOM events and mozChromeEvents will be pending until
+// this observer message is sent.
+Services.obs.notifyObservers(null, 'system-message-listener-ready', null);
 
 function openWindow(aEvent) {
   var popupIframe = aEvent.detail.frameElement;