Change Page::m_mainFrame to be a Frame.

Source/core/loader/NavigationScheduler.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2009 Adam Barth. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
@@ skipping 172 matching lines @@
         if (!m_historySteps) {
             FrameLoadRequest frameRequest(frame->document(), ResourceRequest(frame->document()->url()));
             frameRequest.setLockBackForwardList(lockBackForwardList());
             // Special case for go(0) from a frame -> reload only the frame
             // To follow Firefox and IE's behavior, history reload can only navigate the self frame.
             frame->loader().load(frameRequest);
             return;
         }
         // go(i!=0) from a frame navigates into the history of the frame only,
         // in both IE and NS (but not in Mozilla). We can't easily do that.
-        frame->page()->mainFrame()->loader().client()->navigateBackForward(m_historySteps);
+        frame->page()->deprecatedLocalMainFrame()->loader().client()->navigateBackForward(m_historySteps);
     }
 
 private:
     int m_historySteps;
 };
 
 class ScheduledFormSubmission FINAL : public ScheduledNavigation {
 public:
     ScheduledFormSubmission(PassRefPtrWillBeRawPtr<FormSubmission> submission, bool lockBackForwardList)
         : ScheduledNavigation(0, lockBackForwardList, true)
@@ skipping 204 matching lines @@
 
 void NavigationScheduler::cancel()
 {
     if (m_timer.isActive())
         InspectorInstrumentation::frameClearedScheduledNavigation(m_frame);
     m_timer.stop();
     m_redirect.clear();
 }
 
 } // namespace WebCore