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

third_party/WebKit/Source/modules/vr/VRDisplay.cpp

 // 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.
 
 #include "modules/vr/VRDisplay.h"
 
 #include "core/css/StylePropertySet.h"
 #include "core/dom/DOMException.h"
 #include "core/dom/DocumentUserGestureToken.h"
 #include "core/dom/FrameRequestCallback.h"
@@ skipping 555 matching lines @@
     rightBounds->width = m_layer.rightBounds()[2];
     rightBounds->height = m_layer.rightBounds()[3];
   } else {
     // Right eye defaults
     rightBounds->left = 0.5f;
     rightBounds->top = 0.0f;
     rightBounds->width = 0.5f;
     rightBounds->height = 1.0f;
   }
 
-  m_display->UpdateLayerBounds(std::move(leftBounds), std::move(rightBounds));
+  // TODO(klausw): Tie updating layer bounds to when we render the correct
+  // frame.
+  // Specify a frame index of 0 for now, meaning to update immediately.
+  m_display->UpdateLayerBounds(0, std::move(leftBounds),
+                               std::move(rightBounds));
 }
 
 HeapVector<VRLayer> VRDisplay::getLayers() {
   HeapVector<VRLayer> layers;
 
   if (m_isPresenting) {
     layers.append(m_layer);
   }
 
   return layers;
@@ skipping 179 matching lines @@
   visitor->trace(m_stageParameters);
   visitor->trace(m_eyeParametersLeft);
   visitor->trace(m_eyeParametersRight);
   visitor->trace(m_layer);
   visitor->trace(m_renderingContext);
   visitor->trace(m_scriptedAnimationController);
   visitor->trace(m_pendingPresentResolvers);
 }
 
 }  // namespace blink