Fix frameElement for frames with a remote parent.

Source/core/frame/LocalDOMWindow.cpp

Index: Source/core/frame/LocalDOMWindow.cpp
diff --git a/Source/core/frame/LocalDOMWindow.cpp b/Source/core/frame/LocalDOMWindow.cpp
index fcbedc571a32e4330605e33fe2ac5c88734d7b2e..80f0a386bc1a4ee58c73934e9478e0c70290ae2b 100644
--- a/Source/core/frame/LocalDOMWindow.cpp
+++ b/Source/core/frame/LocalDOMWindow.cpp
@@ -733,7 +733,7 @@ DOMSelection* LocalDOMWindow::getSelection()
 
 Element* LocalDOMWindow::frameElement() const
 {
-    if (!frame())
+    if (!frame() || (frame()->owner() && !frame()->owner()->isLocal()))

[alexmos, 2015/04/30 20:45:26]

The comment about the binding security check below implies that frameElement()
is expected to be called only when the frame and parent are same-origin.  Do we
want to keep this, or should we return nullptr for the remote case as opposed to
hitting the ASSERT below?  The fix in this CL doesn't need this change; I'm just
curious what you think.

[dcheng, 2015/04/30 20:58:51]

I'd prefer to just hit the assert below. deprecatedLocalOwner() will also assert
(though since we're in this code, it might be good to just change that to
toHTMLFrameOwnerElement(frame()->owner(), so we know this particular usage is
"kosher").

[alexmos, 2015/04/30 21:12:58]

Sounds good -- done.

         return nullptr;
 
     // The bindings security check should ensure we're same origin...