Change Page::m_mainFrame to be a Frame.

Source/core/page/PageAnimator.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/page/PageAnimator.h"
 
 #include "core/animation/DocumentAnimations.h"
 #include "core/dom/Document.h"
 #include "core/frame/FrameView.h"
@@ skipping 47 matching lines @@
 void PageAnimator::scheduleVisualUpdate()
 {
     // FIXME: also include m_animationFramePending here. It is currently not there due to crbug.com/353756.
     if (m_servicingAnimations || m_updatingLayoutAndStyleForPainting)
         return;
     m_page->chrome().scheduleAnimation();
 }
 
 void PageAnimator::updateLayoutAndStyleForPainting()
 {
-    RefPtr<FrameView> view = m_page->mainFrame()->view();
+    if (!m_page->mainFrame()->isLocalFrame())
+        return;
+
+    RefPtr<FrameView> view = m_page->deprecatedLocalMainFrame()->view();
 
     TemporaryChange<bool> servicing(m_updatingLayoutAndStyleForPainting, true);
 
     // In order for our child HWNDs (NativeWindowWidgets) to update properly,
     // they need to be told that we are updating the screen. The problem is that
     // the native widgets need to recalculate their clip region and not overlap
     // any of our non-native widgets. To force the resizing, call
     // setFrameRect(). This will be a quick operation for most frames, but the
     // NativeWindowWidgets will update a proper clipping region.
     view->setFrameRect(view->frameRect());
 
     // setFrameRect may have the side-effect of causing existing page layout to
     // be invalidated, so layout needs to be called last.
     view->updateLayoutAndStyleForPainting();
 }
 
 }