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..f3bb8c7ffafdae3c76822ceff1568b43f5cbe9cf 100644
--- a/Source/core/page/Page.h
+++ b/Source/core/page/Page.h
@@ -22,6 +22,7 @@
 #define Page_h
 
 #include "core/dom/ViewportDescription.h"
+#include "core/frame/LocalFrame.h"
 #include "core/frame/SettingsDelegate.h"
 #include "core/frame/UseCounter.h"
 #include "core/page/PageAnimator.h"
@@ -51,7 +52,7 @@ class DragClient;
 class DragController;
 class EditorClient;
 class FocusController;
-class LocalFrame;
+class Frame;
 class FrameHost;
 class HistoryItem;
 class InspectorClient;
@@ -127,8 +128,14 @@ 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(); }
+    // Escape hatch for existing code that assumes that the root frame is
+    // always a LocalFrame. With OOPI, this is not always the case. Code that
+    // depends on this will generally have to be rewritten to propagate any
+    // necessary state through all renderer processes for that page and/or
+    // coordinate/rely on the browser process to help dispatch/coordinate work.
+    LocalFrame* deprecatedLocalMainFrame() const { return toLocalFrame(m_mainFrame.get()); }
 
     void documentDetached(Document*);
 
@@ -252,7 +259,7 @@ private:
     OwnPtr<ScrollingCoordinator> m_scrollingCoordinator;
     const OwnPtr<UndoStack> m_undoStack;
 
-    RefPtr<LocalFrame> m_mainFrame;
+    RefPtr<Frame> m_mainFrame;
 
     mutable RefPtr<PluginData> m_pluginData;