Bug 1264784 - part 1 - call nsIFrame::{GetScreenRect,GetView} instead of their *External counterparts; r=dholbert

The latter functions just call through to the former functions, and
we're going to remove the latter functions in a separate, subsequent
patch.

accessible/base/nsCoreUtils.cpp

@@ -113,7 +113,7 @@ nsCoreUtils::DispatchClickEvent(nsITreeBoxObject *aTreeBoxObj,
 
   nsPoint offset;
   nsIWidget *rootWidget =
-    rootFrame->GetViewExternal()->GetNearestWidget(&offset);
+    rootFrame->GetView()->GetNearestWidget(&offset);
 
   RefPtr<nsPresContext> presContext = presShell->GetPresContext();