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

device/vr/android/gvr/gvr_device.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_ANDROID_GVR_DEVICE_H
 #define DEVICE_VR_ANDROID_GVR_DEVICE_H
 
 #include "base/macros.h"
 #include "device/vr/vr_device.h"
 
@@ skipping 13 matching lines @@
 
   // VRDevice
   mojom::VRDisplayInfoPtr GetVRDevice() override;
   void ResetPose() override;
 
   void RequestPresent(const base::Callback<void(bool)>& callback) override;
   void SetSecureOrigin(bool secure_origin) 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 SetDelegate(GvrDelegate* delegate);
 
  private:
   gvr::GvrApi* GetGvrApi();
 
   GvrDelegate* delegate_;
   GvrDeviceProvider* gvr_provider_;
   bool secure_origin_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(GvrDevice);
 };
 
 }  // namespace device
 
 #endif  // DEVICE_VR_ANDROID_GVR_DEVICE_H