Change Page::m_mainFrame to be a Frame.

Source/core/inspector/InspectorLayerTreeAgent.cpp

 /*
  * Copyright (C) 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 151 matching lines @@
 void InspectorLayerTreeAgent::restore()
 {
     // We do not re-enable layer agent automatically after navigation. This is because
     // it depends on DOMAgent and node ids in particular, so we let front-end request document
     // and re-enable the agent manually after this.
 }
 
 void InspectorLayerTreeAgent::enable(ErrorString*)
 {
     m_instrumentingAgents->setInspectorLayerTreeAgent(this);
-    if (LocalFrame* frame = m_page->mainFrame()) {
+    if (LocalFrame* frame = toLocalFrame(m_page->mainFrame())) {
         Document* document = frame->document();
         if (document && document->lifecycle().state() >= DocumentLifecycle::CompositingClean)
             layerTreeDidChange();
     }
 }
 
 void InspectorLayerTreeAgent::disable(ErrorString*)
 {
     m_instrumentingAgents->setInspectorLayerTreeAgent(0);
     m_snapshotById.clear();
@@ skipping 63 matching lines @@
         gatherGraphicsLayers(root->children()[i], layerIdToNodeIdMap, layers);
 }
 
 int InspectorLayerTreeAgent::idForNode(Node* node)
 {
     return InspectorNodeIds::idForNode(node);
 }
 
 RenderLayerCompositor* InspectorLayerTreeAgent::renderLayerCompositor()
 {
-    RenderView* renderView = m_page->mainFrame()->contentRenderer();
+    RenderView* renderView = toLocalFrame(m_page->mainFrame())->contentRenderer();
     RenderLayerCompositor* compositor = renderView ? renderView->compositor() : 0;
     return compositor;
 }
 
 static GraphicsLayer* findLayerById(GraphicsLayer* root, int layerId)
 {
     if (root->platformLayer()->id() == layerId)
         return root;
     if (root->replicaLayer()) {
         if (GraphicsLayer* layer = findLayerById(root->replicaLayer(), layerId))
@@ skipping 138 matching lines @@
 void InspectorLayerTreeAgent::didRemovePageOverlay(const GraphicsLayer* layer)
 {
     size_t index = m_pageOverlayLayerIds.find(layer->platformLayer()->id());
     if (index == WTF::kNotFound)
         return;
     m_pageOverlayLayerIds.remove(index);
 }
 
 
 } // namespace WebCore