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

mojo/examples/compositor_app/compositor_host.h

 // Copyright 2013 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_EXAMPLES_COMPOSITOR_APP_COMPOSITOR_HOST_H_
 #define MOJO_EXAMPLES_COMPOSITOR_APP_COMPOSITOR_HOST_H_
 
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/threading/thread.h"
@@ skipping 15 matching lines @@
   explicit CompositorHost(ScopedMessagePipeHandle command_buffer_handle);
   virtual ~CompositorHost();
 
   void SetSize(const gfx::Size& viewport_size);
 
   // 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;
 
  private:
   void SetupScene();
 
   ScopedMessagePipeHandle command_buffer_handle_;
   scoped_ptr<cc::LayerTreeHost> tree_;
   scoped_refptr<cc::Layer> child_layer_;
   base::Thread compositor_thread_;
 };
 
 }  // namespace examples
 }  // namespace mojo
 
 #endif  // MOJO_EXAMPLES_COMPOSITOR_APP_COMPOSITOR_HOST_H_