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

device/vr/vr_display_impl.cc

Index: device/vr/vr_display_impl.cc
diff --git a/device/vr/vr_display_impl.cc b/device/vr/vr_display_impl.cc
index b4025dd80af2b7b757cea111322fed066f377f50..8a40667fe8dd20fdb7c949f1d9ea1fba18d01f60 100644
--- a/device/vr/vr_display_impl.cc
+++ b/device/vr/vr_display_impl.cc
@@ -76,11 +76,13 @@ void VRDisplayImpl::SubmitFrame(mojom::VRPosePtr pose) {
   device_->SubmitFrame(std::move(pose));
 }
 
-void VRDisplayImpl::UpdateLayerBounds(mojom::VRLayerBoundsPtr left_bounds,
+void VRDisplayImpl::UpdateLayerBounds(uint32_t frame_index,
+                                      mojom::VRLayerBoundsPtr left_bounds,
                                       mojom::VRLayerBoundsPtr right_bounds) {
   if (!device_->IsAccessAllowed(this))
     return;
 
-  device_->UpdateLayerBounds(std::move(left_bounds), std::move(right_bounds));
+  device_->UpdateLayerBounds(frame_index, std::move(left_bounds),
+                             std::move(right_bounds));
 }
 }