Change Page::m_mainFrame to be a Frame.

Source/core/page/Page.h

Index: Source/core/page/Page.h
diff --git a/Source/core/page/Page.h b/Source/core/page/Page.h
index 73d68ebad551aebb2fd4b0b61daf2741113fc127..bd2d6bc4b36d8bc212aae0e0ca88f7b91353ecbb 100644
--- a/Source/core/page/Page.h
+++ b/Source/core/page/Page.h
@@ -51,6 +51,7 @@ class DragClient;
 class DragController;
 class EditorClient;
 class FocusController;
+class Frame;
 class LocalFrame;
 class FrameHost;
 class HistoryItem;
@@ -127,8 +128,8 @@ public:
     SpellCheckerClient& spellCheckerClient() const { return *m_spellCheckerClient; }
     UndoStack& undoStack() const { return *m_undoStack; }
 
-    void setMainFrame(PassRefPtr<LocalFrame>);
-    LocalFrame* mainFrame() const { return m_mainFrame.get(); }
+    void setMainFrame(PassRefPtr<Frame>);
+    Frame* mainFrame() const { return m_mainFrame.get(); }
 
     void documentDetached(Document*);
 
@@ -252,7 +253,7 @@ private:
     OwnPtr<ScrollingCoordinator> m_scrollingCoordinator;
     const OwnPtr<UndoStack> m_undoStack;
 
-    RefPtr<LocalFrame> m_mainFrame;
+    RefPtr<Frame> m_mainFrame;
 
     mutable RefPtr<PluginData> m_pluginData;