Revert 170347 "Convert HTMLFrameOwnerElement and FocusController..."

Source/core/dom/TreeScope.cpp

Index: Source/core/dom/TreeScope.cpp
===================================================================
--- Source/core/dom/TreeScope.cpp	(revision 170478)
+++ Source/core/dom/TreeScope.cpp	(working copy)
@@ -345,10 +345,8 @@
 {
     Document& document = rootNode().document();
     Element* element = document.focusedElement();
-    // FIXME(kenrb): The toLocalFrame() cast should be removed when RemoteFrames can have FrameTrees.
-    // At that point, focusedFrameOwnerElement should take a Frame instead of a LocalFrame.
     if (!element && document.page())
-        element = focusedFrameOwnerElement(toLocalFrameTemporary(document.page()->focusController().focusedFrame()), document.frame());
+        element = focusedFrameOwnerElement(document.page()->focusController().focusedFrame(), document.frame());
     if (!element)
         return 0;