Bug 1020801 - Add new 'ScrollViewChangeEvent' DOM event. r=fabrice, r=bz

b2g/chrome/content/shell.js

@@ -332,6 +332,7 @@ var shell = {
     window.addEventListener('unload', this);
     this.contentBrowser.addEventListener('mozbrowserloadstart', this, true);
     this.contentBrowser.addEventListener('mozbrowserselectionchange', this, true);
+    this.contentBrowser.addEventListener('mozbrowserscrollviewchange', this, true);
 
     CustomEventManager.init();
     WebappsHelper.init();
@@ -359,6 +360,7 @@ var shell = {
     window.removeEventListener('sizemodechange', this);
     this.contentBrowser.removeEventListener('mozbrowserloadstart', this, true);
     this.contentBrowser.removeEventListener('mozbrowserselectionchange', this, true);
+    this.contentBrowser.removeEventListener('mozbrowserscrollviewchange', this, true);
     ppmm.removeMessageListener("content-handler", this);
 
     UserAgentOverrides.uninit();
@@ -500,7 +502,12 @@ var shell = {
 
         this.notifyContentStart();
        break;
-
+      case 'mozbrowserscrollviewchange':
+        this.sendChromeEvent({
+          type: 'scrollviewchange',
+          detail: evt.detail,
+        });
+        break;
       case 'mozbrowserselectionchange':
         // The mozbrowserselectionchange event, may have crossed the chrome-content boundary.
         // This event always dispatch to shell.js. But the offset we got from this event is

dom/browser-element/BrowserElementChildPreload.js

@@ -221,6 +221,11 @@ BrowserElementChild.prototype = {
                      /* useCapture = */ false,
                      /* wantsUntrusted = */ false);
 
+    addEventListener('scrollviewchange',
+                     this._ScrollViewChangeHandler.bind(this),
+                     /* useCapture = */ false,
+                     /* wantsUntrusted = */ false);
+
     // This listens to unload events from our message manager, but /not/ from
     // the |content| window.  That's because the window's unload event doesn't
     // bubble, and we're not using a capturing listener.  If we'd used
@@ -626,6 +631,16 @@ BrowserElementChild.prototype = {
     sendAsyncMsg('metachange', meta);
   },
 
+  _ScrollViewChangeHandler: function(e) {
+    e.stopPropagation();
+    let detail = {
+      state: e.state,
+      scrollX: e.scrollX,
+      scrollY: e.scrollY,
+    };
+    sendAsyncMsg('scrollviewchange', detail);
+  },
+
   _selectionChangeHandler: function(e) {
     e.stopPropagation();
     let boundingClientRect = e.boundingClientRect;
@@ -666,7 +681,7 @@ BrowserElementChild.prototype = {
       currentWindow = currentWindow.parent;
     }
 
-    sendAsyncMsg("selectionchange", detail);
+    sendAsyncMsg('selectionchange', detail);
   },
 
   _themeColorChangedHandler: function(eventType, target) {

dom/browser-element/BrowserElementParent.jsm

@@ -255,7 +255,8 @@ BrowserElementParent.prototype = {
       "got-visible": this._gotDOMRequestResult,
       "visibilitychange": this._childVisibilityChange,
       "got-set-input-method-active": this._gotDOMRequestResult,
-      "selectionchange": this._handleSelectionChange
+      "selectionchange": this._handleSelectionChange,
+      "scrollviewchange": this._handleScrollViewChange
     };
 
     let mmSecuritySensitiveCalls = {
@@ -496,6 +497,12 @@ BrowserElementParent.prototype = {
     this._frameElement.dispatchEvent(evt);
   },
 
+  _handleScrollViewChange: function(data) {
+    let evt = this._createEvent("scrollviewchange", data.json,
+                                /* cancelable = */ false);
+    this._frameElement.dispatchEvent(evt);
+  },
+
   _createEvent: function(evtName, detail, cancelable) {
     // This will have to change if we ever want to send a CustomEvent with null
     // detail.  For now, it's OK.

dom/webidl/ScrollViewChangeEvent.webidl

@@ -0,0 +1,21 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+enum ScrollState {"started", "stopped"};
+
+dictionary ScrollViewChangeEventInit : EventInit {
+  ScrollState state = "started";
+  float scrollX = 0;
+  float scrollY = 0;
+};
+
+[Constructor(DOMString type, optional ScrollViewChangeEventInit eventInit),
+ ChromeOnly]
+interface ScrollViewChangeEvent : Event {
+  readonly attribute ScrollState state;
+  readonly attribute float scrollX;
+  readonly attribute float scrollY;
+};

dom/webidl/moz.build

@@ -680,6 +680,7 @@ GENERATED_EVENTS_WEBIDL_FILES = [
     'RTCPeerConnectionIceEvent.webidl',
     'RTCPeerConnectionIdentityErrorEvent.webidl',
     'RTCPeerConnectionIdentityEvent.webidl',
+    'ScrollViewChangeEvent.webidl',
     'SelectionChangeEvent.webidl',
     'StyleRuleChangeEvent.webidl',
     'StyleSheetApplicableStateChangeEvent.webidl',