Bug 775448: Disable async scrolling when we detect a scrollable subframe r=cjones

dom/browser-element/BrowserElementScrolling.js

@@ -43,6 +43,16 @@ const ContentPanning = {
     let oldTarget = this.target;
     [this.target, this.scrollCallback] = this.getPannable(evt.target);
 
+    // If we found a target, that means we have found a scrollable subframe. In
+    // this case, and if we are using async panning and zooming on the parent
+    // frame, inform the pan/zoom controller that it should not attempt to
+    // handle any touch events it gets until the next batch (meaning the next
+    // time we get a touch end).
+    if (this.target != null && ContentPanning._asyncPanZoomForViewportFrame) {
+      var os = Cc["@mozilla.org/observer-service;1"].getService(Ci.nsIObserverService);
+      os.notifyObservers(docShell, 'cancel-default-pan-zoom', null);
+    }
+
     // If there is a pan animation running (from a previous pan gesture) and
     // the user touch back the screen, stop this animation immediatly and
     // prevent the possible click action if the touch happens on the same

dom/ipc/TabChild.cpp

@@ -120,6 +120,12 @@ TabChild::Observe(nsISupports *aSubject,
     if (win == topSubject) {
       SendNotifyDOMTouchListenerAdded();
     }
+  } else if (!strcmp(aTopic, "cancel-default-pan-zoom")) {
+    nsCOMPtr<nsIDocShell> docShell(do_QueryInterface(aSubject));
+    nsCOMPtr<nsITabChild> tabChild(GetTabChildFrom(docShell));
+    if (tabChild == this) {
+      mRemoteFrame->CancelDefaultPanZoom();
+    }
   }
 
   return NS_OK;
@@ -148,6 +154,9 @@ TabChild::Init()
     observerService->AddObserver(this,
                                  "dom-touch-listener-added",
                                  false);
+    observerService->AddObserver(this,
+                                 "cancel-default-pan-zoom",
+                                 false);
   }
 
   return NS_OK;

gfx/layers/ipc/AsyncPanZoomController.cpp

@@ -54,7 +54,8 @@ AsyncPanZoomController::AsyncPanZoomController(GeckoContentController* aGeckoCon
      mState(NOTHING),
      mDPI(72),
      mContentPainterStatus(CONTENT_IDLE),
-     mMayHaveTouchListeners(false)
+     mMayHaveTouchListeners(false),
+     mDisableNextTouchBatch(false)
 {
   if (aGestures == USE_GESTURE_DETECTOR) {
     mGestureEventListener = new GestureEventListener(this);
@@ -223,6 +224,10 @@ nsEventStatus AsyncPanZoomController::OnTouchStart(const MultiTouchInput& aEvent
 }
 
 nsEventStatus AsyncPanZoomController::OnTouchMove(const MultiTouchInput& aEvent) {
+  if (mDisableNextTouchBatch) {
+    return nsEventStatus_eIgnore;
+  }
+
   switch (mState) {
     case FLING:
     case NOTHING:
@@ -254,6 +259,11 @@ nsEventStatus AsyncPanZoomController::OnTouchMove(const MultiTouchInput& aEvent)
 }
 
 nsEventStatus AsyncPanZoomController::OnTouchEnd(const MultiTouchInput& aEvent) {
+  if (mDisableNextTouchBatch) {
+    mDisableNextTouchBatch = false;
+    return nsEventStatus_eIgnore;
+  }
+
   switch (mState) {
   case FLING:
     // Should never happen.
@@ -811,5 +821,9 @@ void AsyncPanZoomController::NotifyDOMTouchListenerAdded() {
   mMayHaveTouchListeners = true;
 }
 
+void AsyncPanZoomController::CancelDefaultPanZoom() {
+  mDisableNextTouchBatch = true;
+}
+
 }
 }

gfx/layers/ipc/AsyncPanZoomController.h

@@ -109,6 +109,16 @@ public:
    */
   void NotifyDOMTouchListenerAdded();
 
+  /**
+   * We have found a scrollable subframe, so disable our machinery until we hit
+   * a touch end or a new touch start. This prevents us from accidentally
+   * panning both the subframe and the parent frame.
+   *
+   * XXX/bug 775452: We should eventually be supporting async scrollable
+   * subframes.
+   */
+  void CancelDefaultPanZoom();
+
   // --------------------------------------------------------------------------
   // These methods must only be called on the compositor thread.
   //
@@ -408,6 +418,10 @@ private:
   // approximation and may not be accurate.
   bool mMayHaveTouchListeners;
 
+  // Flag used to determine whether or not we should disable handling of the
+  // next batch of touch events. This is used for sync scrolling of subframes.
+  bool mDisableNextTouchBatch;
+
   friend class Axis;
 };
 

layout/ipc/PRenderFrame.ipdl

@@ -41,6 +41,8 @@ parent:
 
     async NotifyCompositorTransaction();
 
+    async CancelDefaultPanZoom();
+
     async __delete__();
 
 state EMPTY_OR_DIRECT_COMPOSITOR:

layout/ipc/RenderFrameChild.cpp

@@ -32,6 +32,12 @@ RenderFrameChild::Destroy()
   // WARNING: |this| is dead, hands off
 }
 
+void
+RenderFrameChild::CancelDefaultPanZoom()
+{
+  SendCancelDefaultPanZoom();
+}
+
 PLayersChild*
 RenderFrameChild::AllocPLayers()
 {

layout/ipc/RenderFrameChild.h

@@ -19,6 +19,8 @@ public:
   RenderFrameChild() {}
   virtual ~RenderFrameChild() {}
 
+  void CancelDefaultPanZoom();
+
   void Destroy();
 
 protected:

layout/ipc/RenderFrameParent.cpp

@@ -720,6 +720,15 @@ RenderFrameParent::RecvNotifyCompositorTransaction()
   return true;
 }
 
+bool
+RenderFrameParent::RecvCancelDefaultPanZoom()
+{
+  if (mPanZoomController) {
+    mPanZoomController->CancelDefaultPanZoom();
+  }
+  return true;
+}
+
 PLayersParent*
 RenderFrameParent::AllocPLayers()
 {

layout/ipc/RenderFrameParent.h

@@ -100,6 +100,8 @@ protected:
 
   virtual bool RecvNotifyCompositorTransaction() MOZ_OVERRIDE;
 
+  virtual bool RecvCancelDefaultPanZoom() MOZ_OVERRIDE;
+
   virtual PLayersParent* AllocPLayers() MOZ_OVERRIDE;
   virtual bool DeallocPLayers(PLayersParent* aLayers) MOZ_OVERRIDE;