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

device/vr/android/gvr/gvr_device.cc

Index: device/vr/android/gvr/gvr_device.cc
diff --git a/device/vr/android/gvr/gvr_device.cc b/device/vr/android/gvr/gvr_device.cc
index 9dc6b39c8118bd81fb277020ed7047060d877c2d..fcbb43797778e313867009b256c68507bf4c8206 100644
--- a/device/vr/android/gvr/gvr_device.cc
+++ b/device/vr/android/gvr/gvr_device.cc
@@ -241,7 +241,8 @@ void GvrDevice::SubmitFrame(mojom::VRPosePtr pose) {
     delegate_->SubmitWebVRFrame();
 }
 
-void GvrDevice::UpdateLayerBounds(mojom::VRLayerBoundsPtr left_bounds,
+void GvrDevice::UpdateLayerBounds(uint32_t frame_index,
+                                  mojom::VRLayerBoundsPtr left_bounds,
                                   mojom::VRLayerBoundsPtr right_bounds) {
   if (!delegate_)
     return;
@@ -258,7 +259,8 @@ void GvrDevice::UpdateLayerBounds(mojom::VRLayerBoundsPtr left_bounds,
   right_gvr_bounds.right = right_bounds->left + right_bounds->width;
   right_gvr_bounds.bottom = 1.0f - (right_bounds->top + right_bounds->height);
 
-  delegate_->UpdateWebVRTextureBounds(left_gvr_bounds, right_gvr_bounds);
+  delegate_->UpdateWebVRTextureBounds(frame_index, left_gvr_bounds,
+                                      right_gvr_bounds);
 }
 
 void GvrDevice::SetDelegate(GvrDelegate* delegate) {