Prevent propagation of wheel events to dispatch event in parent iframe.

third_party/WebKit/Source/core/input/EventHandler.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2012 Digia Plc. and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 1772 matching lines @@
 
     HitTestRequest request(HitTestRequest::ReadOnly);
     HitTestResult result(request, vPoint);
     doc->layoutView()->hitTest(result);
 
     Node* node = result.innerNode();
     // Wheel events should not dispatch to text nodes.
     if (node && node->isTextNode())
         node = FlatTreeTraversal::parent(*node);
 
-    bool isOverWidget = result.isOverWidget();
+    bool sendDOMEvent = true;
+    LocalFrame* subframe = subframeForTargetNode(node);
+    if (subframe) {
+        WebInputEventResult result = subframe->eventHandler().handleWheelEvent(event);
+        if (result != WebInputEventResult::NotHandled) {
+            setFrameWasScrolledByUser();
+            return result;
+        }
+        // TODO(dtapuska): Remove this once wheel gesture scroll has
+        // been enabled everywhere; as we can just return early.
+        // http://crbug.com/568183
+        // Don't propagate the DOM event into the parent iframe
+        // but do dispatch the scroll event.
+        sendDOMEvent = false;
+    }
 
-    if (node) {
-        // Figure out which view to send the event to.
-        LayoutObject* target = node->layoutObject();
-
-        if (isOverWidget && target && target->isLayoutPart()) {
-            if (Widget* widget = toLayoutPart(target)->widget()) {
-                WebInputEventResult result = passWheelEventToWidget(event, *widget);
-                if (result != WebInputEventResult::NotHandled) {
-                    setFrameWasScrolledByUser();
-                    return result;
-                }
-            }
-        }
-
+    if (node && sendDOMEvent) {
         RefPtrWillBeRawPtr<Event> domEvent = WheelEvent::create(event, node->document().domWindow());
         DispatchEventResult domEventResult = node->dispatchEvent(domEvent);
         if (domEventResult != DispatchEventResult::NotCanceled) {
             setFrameWasScrolledByUser();
             return toWebInputEventResult(domEventResult);
         }
     }
 
     // We do another check on the frame view because the event handler can run
     // JS which results in the frame getting destroyed.
@@ skipping 2123 matching lines @@
 }
 
 WebInputEventResult EventHandler::passMouseReleaseEventToSubframe(MouseEventWithHitTestResults& mev, LocalFrame* subframe)
 {
     WebInputEventResult result = subframe->eventHandler().handleMouseReleaseEvent(mev.event());
     if (result != WebInputEventResult::NotHandled)
         return result;
     return WebInputEventResult::HandledSystem;
 }
 
-WebInputEventResult EventHandler::passWheelEventToWidget(const PlatformWheelEvent& wheelEvent, Widget& widget)
-{
-    // If not a FrameView, then probably a plugin widget.  Those will receive
-    // the event via an EventTargetNode dispatch when this returns false.
-    if (!widget.isFrameView())
-        return WebInputEventResult::NotHandled;
-
-    return toFrameView(&widget)->frame().eventHandler().handleWheelEvent(wheelEvent);
-}
-
 DataTransfer* EventHandler::createDraggingDataTransfer() const
 {
     return DataTransfer::create(DataTransfer::DragAndDrop, DataTransferWritable, DataObject::create());
 }
 
 void EventHandler::focusDocumentView()
 {
     Page* page = m_frame->page();
     if (!page)
         return;
     page->focusController().focusDocumentView(m_frame);
 }
 
 PlatformEvent::Modifiers EventHandler::accessKeyModifiers()
 {
 #if OS(MACOSX)
     return static_cast<PlatformEvent::Modifiers>(PlatformEvent::CtrlKey | PlatformEvent::AltKey);
 #else
     return PlatformEvent::AltKey;
 #endif
 }
 
 } // namespace blink