Add Frame::isMainFrame and deploy it

Source/core/loader/HistoryController.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 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/)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
@@ skipping 67 matching lines @@
  which case the restore silent fails and we will fix it in when we try to restore on doc completion.
  2) If the layout happens after the load completes, the attempt to restore at load completion time silently
  fails.  We then successfully restore it when the layout happens.
 */
 void HistoryController::restoreScrollPositionAndViewState()
 {
     if (!m_currentItem || !m_frame->loader().stateMachine()->committedFirstRealDocumentLoad())
         return;
 
     if (FrameView* view = m_frame->view()) {
-        Page* page = m_frame->page();
-        if (page && page->mainFrame() == m_frame) {
-            if (ScrollingCoordinator* scrollingCoordinator = page->scrollingCoordinator())
+        if (m_frame->isMainFrame()) {
+            if (ScrollingCoordinator* scrollingCoordinator = m_frame->page()->scrollingCoordinator())
                 scrollingCoordinator->frameViewRootLayerDidChange(view);
         }
 
         if (!view->wasScrolledByUser()) {
-            if (page && page->mainFrame() == m_frame && m_currentItem->pageScaleFactor())
-                page->setPageScaleFactor(m_currentItem->pageScaleFactor(), m_currentItem->scrollPoint());
+            if (m_frame->isMainFrame() && m_currentItem->pageScaleFactor())
+                m_frame->page()->setPageScaleFactor(m_currentItem->pageScaleFactor(), m_currentItem->scrollPoint());
             else
                 view->setScrollPositionNonProgrammatically(m_currentItem->scrollPoint());
         }
     }
 }
 
 void HistoryController::updateBackForwardListForFragmentScroll()
 {
     createNewBackForwardItem(false);
 }
@@ skipping 10 matching lines @@
         LOG(Loading, "WebCoreLoading %s: saving form state to %p", m_frame->tree().uniqueName().string().utf8().data(), m_currentItem.get());
         m_currentItem->setDocumentState(document->formElementsState());
     }
 
     if (!m_frame->view())
         return;
 
     m_currentItem->setScrollPoint(m_frame->view()->scrollPosition());
 
     Page* page = m_frame->page();
-    if (page && page->mainFrame() == m_frame && !page->inspectorController().deviceEmulationEnabled())
+    if (m_frame->isMainFrame() && !page->inspectorController().deviceEmulationEnabled())
         m_currentItem->setPageScaleFactor(page->pageScaleFactor());
 }
 
 void HistoryController::restoreDocumentState()
 {
     if (m_currentItem && m_frame->loader().loadType() == FrameLoadTypeBackForward)
         m_frame->document()->setStateForNewFormElements(m_currentItem->documentState());
 }
 
 bool HistoryController::shouldStopLoadingForHistoryItem(HistoryItem* targetItem) const
@@ skipping 418 matching lines @@
     if (!urlString.isEmpty())
         m_currentItem->setURLString(urlString);
     m_currentItem->setStateObject(stateObject);
     m_currentItem->setFormData(0);
     m_currentItem->setFormContentType(String());
 
     ASSERT(m_frame->page());
 }
 
 } // namespace WebCore