Extract a DOMWindow interface from LocalDOMWindow and use it in the idl.

Source/core/events/MouseRelatedEvent.cpp

Index: Source/core/events/MouseRelatedEvent.cpp
diff --git a/Source/core/events/MouseRelatedEvent.cpp b/Source/core/events/MouseRelatedEvent.cpp
index 9b7f32ec3a37666eff6bb73e64b3b17a7e226d55..42351626b9024296bcdc57d557f959ee7ebc096e 100644
--- a/Source/core/events/MouseRelatedEvent.cpp
+++ b/Source/core/events/MouseRelatedEvent.cpp
@@ -40,9 +40,9 @@ MouseRelatedEvent::MouseRelatedEvent()
 
 static LayoutSize contentsScrollOffset(AbstractView* abstractView)
 {
-    if (!abstractView)
+    if (!abstractView || !abstractView->isLocalDOMWindow())
         return LayoutSize();
-    LocalFrame* frame = abstractView->frame();
+    LocalFrame* frame = toLocalDOMWindow(abstractView)->frame();
     if (!frame)
         return LayoutSize();
     FrameView* frameView = frame->view();
@@ -64,7 +64,7 @@ MouseRelatedEvent::MouseRelatedEvent(const AtomicString& eventType, bool canBubb
     LayoutPoint adjustedPageLocation;
     LayoutPoint scrollPosition;
 
-    LocalFrame* frame = view() ? view()->frame() : 0;
+    LocalFrame* frame = view() && view()->isLocalDOMWindow() ? toLocalDOMWindow(view())->frame() : 0;

[dcheng, 2014/10/31 03:20:41]

It was quite a surprise to me that you can pass arbitrary Window objects to
initMouseEvent, etc. Right now, this means web pages could potentially inspect
the page zoom factor cross origin. With this change (and actual
RemoteDOMWindows), this would no longer be possible. I don't think this will be
a web compat problem, but I'm not 100% sure.

     if (frame && !isSimulated) {
         if (FrameView* frameView = frame->view()) {
             scrollPosition = frameView->scrollPosition();
@@ -110,10 +110,9 @@ void MouseRelatedEvent::initCoordinates(const LayoutPoint& clientLocation)
 
 static float pageZoomFactor(const UIEvent* event)
 {
-    LocalDOMWindow* window = event->view();
-    if (!window)
+    if (!event->view() || !event->view()->isLocalDOMWindow())
         return 1;
-    LocalFrame* frame = window->frame();
+    LocalFrame* frame = toLocalDOMWindow(event->view())->frame();
     if (!frame)
         return 1;
     return frame->pageZoomFactor();