Allow VRDisplay to specify which frame the layer bounds should be updated at.

chrome/browser/android/vr_shell/vr_shell_gl.h

 // Copyright 2016 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 CHROME_BROWSER_ANDROID_VR_SHELL_VR_SHELL_GL_H_
 #define CHROME_BROWSER_ANDROID_VR_SHELL_VR_SHELL_GL_H_
 
 #include <memory>
 
 #include "base/cancelable_callback.h"
@@ skipping 59 matching lines @@
   void OnPause();
   void OnResume();
 
   void SetWebVrMode(bool enabled);
   void ContentBoundsChanged(int width, int height);
   void ContentPhysicalBoundsChanged(int width, int height);
   void UIBoundsChanged(int width, int height);
   void UIPhysicalBoundsChanged(int width, int height);
   base::WeakPtr<VrShellGl> GetWeakPtr();
 
-  void UpdateWebVRTextureBounds(const gvr::Rectf& left_bounds,
+  void UpdateWebVRTextureBounds(uint32_t frame_index,
+                                const gvr::Rectf& left_bounds,
                                 const gvr::Rectf& right_bounds);
   gvr::GvrApi* gvr_api();
   void SetGvrPoseForWebVr(const gvr::Mat4f& pose, uint32_t pose_num);
   gvr::Sizei GetWebVRCompositorSurfaceSize();
 
   void UpdateScene(std::unique_ptr<base::ListValue> commands);
 
  private:
   void GvrInit(gvr_context* gvr_api);
   void InitializeRenderer();
@@ skipping 89 matching lines @@
   scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner_;
 
   base::WeakPtrFactory<VrShellGl> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(VrShellGl);
 };
 
 }  // namespace vr_shell
 
 #endif  // CHROME_BROWSER_ANDROID_VR_SHELL_VR_SHELL_GL_H_