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

device/vr/vr_display_impl.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 DEVICE_VR_VR_DISPLAY_IMPL_H
 #define DEVICE_VR_VR_DISPLAY_IMPL_H
 
 #include <memory>
 
 #include "base/macros.h"
@@ skipping 18 matching lines @@
   friend class VRDisplayImplTest;
   friend class VRServiceImpl;
 
   void ResetPose() override;
 
   void RequestPresent(bool secure_origin,
                       const RequestPresentCallback& callback) override;
   void ExitPresent() override;
   void SubmitFrame(mojom::VRPosePtr pose) override;
 
-  void UpdateLayerBounds(mojom::VRLayerBoundsPtr left_bounds,
+  void UpdateLayerBounds(int16_t frame_index,
+                         mojom::VRLayerBoundsPtr left_bounds,
                          mojom::VRLayerBoundsPtr right_bounds) override;
   void GetVRVSyncProvider(mojom::VRVSyncProviderRequest request) override;
 
   void RequestPresentResult(const RequestPresentCallback& callback,
                             bool secure_origin,
                             bool success);
 
   mojo::Binding<mojom::VRDisplay> binding_;
   mojom::VRDisplayClientPtr client_;
   device::VRDevice* device_;
   VRServiceImpl* service_;
 
   base::WeakPtrFactory<VRDisplayImpl> weak_ptr_factory_;
 };
 
 }  // namespace device
 
 #endif  //  DEVICE_VR_VR_DISPLAY_IMPL_H