Added pinch viewport offset to history item.

Source/core/page/Page.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All Rights Reserved.
  * Copyright (C) 2008 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 305 matching lines @@
 }
 
 void Page::setPageScaleFactor(float scale, const IntPoint& origin)
 {
     FrameView* view = mainFrame()->view();
     PinchViewport& viewport = frameHost().pinchViewport();
 
     if (scale != viewport.scale()) {
         viewport.setScale(scale);
 
-        if (view)
+        if (view && !settings().pinchVirtualViewportEnabled())
             view->setVisibleContentScaleFactor(scale);
 
         mainFrame()->deviceOrPageScaleFactorChanged();
         m_chrome->client().deviceOrPageScaleFactorChanged();
 
         if (view)
             view->viewportConstrainedVisibleContentSizeChanged(true, true);
 
         mainFrame()->loader().saveScrollState();
     }
@@ skipping 247 matching lines @@
     , spellCheckerClient(0)
     , storageClient(0)
 {
 }
 
 Page::PageClients::~PageClients()
 {
 }
 
 } // namespace WebCore