Made double-tap zoom work in pinch virtual viewport mode. (Blink-side)

public/web/WebWidget.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * 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.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 135 matching lines @@
     // Check whether the given point hits any registered touch event handlers.
     virtual bool hasTouchEventHandlersAt(const WebPoint&) { return true; }
 
     // Applies viewport related properties during a commit from the compositor
     // thread.
     virtual void applyViewportDeltas(
         const WebSize& scrollDelta,
         float scaleFactor,
         float topControlsDelta) { }
 
+    // Applies viewport related properties during a commit from the compositor
+    // thread.
+    virtual void applyViewportDeltas(
+        const WebSize& pinchViewportDelta,
+        const WebSize& mainFrameDelta,
+        float scaleFactor,
+        float topControlsDelta) { }
+
     // Called to inform the WebWidget that mouse capture was lost.
     virtual void mouseCaptureLost() { }
 
     // Called to inform the WebWidget that it has gained or lost keyboard focus.
     virtual void setFocus(bool) { }
 
     // Called to inform the WebWidget of a new composition text.
     // If selectionStart and selectionEnd has the same value, then it indicates
     // the input caret position. If the text is empty, then the existing
     // composition text will be cancelled.
@@ skipping 96 matching lines @@
     // but not the select popup.
     virtual WebPagePopup* pagePopup() const { return 0; }
 
 protected:
     ~WebWidget() { }
 };
 
 } // namespace blink
 
 #endif