Add touchpad pinch zoom support to Blink

Source/web/ChromeClientImpl.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 511 matching lines @@
     webframe->didChangeContentsSize(size);
 
     frame->loader().restoreScrollPositionAndViewState();
 }
 
 void ChromeClientImpl::pageScaleFactorChanged() const
 {
     m_webView->pageScaleFactorChanged();
 }
 
+float ChromeClientImpl::clampPageScaleFactorToLimits(float scale) const
+{
+    return m_webView->clampPageScaleFactorToLimits(scale);
+}
+
 void ChromeClientImpl::layoutUpdated(LocalFrame* frame) const
 {
     m_webView->layoutUpdated(WebLocalFrameImpl::fromFrame(frame));
 }
 
 void ChromeClientImpl::mouseDidMoveOverElement(const HitTestResult& result)
 {
     if (!m_webView->client())
         return;
 
@@ skipping 339 matching lines @@
         webframe->autofillClient()->dataListOptionsChanged(WebInputElement(&input));
 }
 
 void ChromeClientImpl::registerViewportLayers() const
 {
     if (m_webView->rootGraphicsLayer() && m_webView->layerTreeView() && m_webView->pinchVirtualViewportEnabled())
         m_webView->page()->frameHost().pinchViewport().registerLayersWithTreeView(m_webView->layerTreeView());
 }
 
 } // namespace blink