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

mojo/services/html_viewer/weblayertreeview_impl.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_SERVICES_HTML_VIEWER_WEBLAYERTREEVIEW_IMPL_H_
 #define MOJO_SERVICES_HTML_VIEWER_WEBLAYERTREEVIEW_IMPL_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
@@ skipping 30 matching lines @@
   virtual ~WebLayerTreeViewImpl();
 
   void set_widget(blink::WebWidget* widget) { widget_ = widget; }
   void set_view(View* view) { view_ = view; }
 
   // cc::LayerTreeHostClient implementation.
   virtual void WillBeginMainFrame(int frame_id) OVERRIDE;
   virtual void DidBeginMainFrame() OVERRIDE;
   virtual void BeginMainFrame(const cc::BeginFrameArgs& args) OVERRIDE;
   virtual void Layout() OVERRIDE;
+  virtual void ApplyViewportDeltas(const gfx::Vector2d& inner_delta,
+                                   const gfx::Vector2d& outer_delta,
+                                   float page_scale,
+                                   float top_controls_delta) OVERRIDE;
   virtual void ApplyViewportDeltas(const gfx::Vector2d& scroll_delta,
                                    float page_scale,
                                    float top_controls_delta) OVERRIDE;
   virtual scoped_ptr<cc::OutputSurface> CreateOutputSurface(
       bool fallback) OVERRIDE;
   virtual void DidInitializeOutputSurface() OVERRIDE;
   virtual void WillCommit() OVERRIDE;
   virtual void DidCommit() OVERRIDE;
   virtual void DidCommitAndDrawFrame() OVERRIDE;
   virtual void DidCompleteSwapBuffers() OVERRIDE;
@@ skipping 62 matching lines @@
       main_thread_compositor_task_runner_;
   base::WeakPtr<WebLayerTreeViewImpl> main_thread_bound_weak_ptr_;
 
   base::WeakPtrFactory<WebLayerTreeViewImpl> weak_factory_;
   DISALLOW_COPY_AND_ASSIGN(WebLayerTreeViewImpl);
 };
 
 }  // namespace mojo
 
 #endif  // MOJO_SERVICES_HTML_VIEWER_WEBLAYERTREEVIEW_IMPL_H_