Provide WebVR pose data only to the focused frame.

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 96 matching lines @@
     OnPresentChange();
   }
 }
 
 void VRDisplay::disconnected() {
   if (m_isConnected)
     m_isConnected = !m_isConnected;
 }
 
 bool VRDisplay::getFrameData(VRFrameData* frameData) {
-  if (!m_framePose || m_displayBlurred)
+  if (!m_navigatorVR->isFocused() || !m_framePose || m_displayBlurred)
     return false;
 
   if (!frameData)
     return false;
 
   if (m_depthNear == m_depthFar)
     return false;
 
   return frameData->update(m_framePose, m_eyeParametersLeft,
                            m_eyeParametersRight, m_depthNear, m_depthFar);
 }
 
 VRPose* VRDisplay::getPose() {
-  if (!m_framePose || m_displayBlurred)
+  if (!m_navigatorVR->isFocused() || !m_framePose || m_displayBlurred)
     return nullptr;
 
   VRPose* pose = VRPose::create();
   pose->setPose(m_framePose);
   return pose;
 }
 
 void VRDisplay::resetPose() {
   if (!m_display)
     return;
@@ skipping 523 matching lines @@
 
   AutoReset<bool> animating(&m_inAnimationFrame, true);
   m_framePose = std::move(pose);
   m_frameId = frameId;
   m_pendingRaf = false;
   m_scriptedAnimationController->serviceScriptedAnimations(
       m_timebase + timeDelta.InSecondsF());
 }
 
 void VRDisplay::ConnectVSyncProvider() {
+  if (!m_navigatorVR->isFocused())
+    return;
   m_display->GetVRVSyncProvider(mojo::MakeRequest(&m_vrVSyncProvider));
   if (m_pendingRaf && !m_displayBlurred) {
     m_vrVSyncProvider->GetVSync(convertToBaseCallback(
         WTF::bind(&VRDisplay::OnVSync, wrapWeakPersistent(this))));
   }
 }
 
 void VRDisplay::onFullscreenCheck(TimerBase*) {
   if (!m_isPresenting) {
     m_fullscreenCheckTimer.stop();
@@ skipping 55 matching lines @@
   forceExitPresent();
   m_scriptedAnimationController.clear();
 }
 
 bool VRDisplay::hasPendingActivity() const {
   // Prevent V8 from garbage collecting the wrapper object if there are
   // event listeners attached to it.
   return getExecutionContext() && hasEventListeners();
 }
 
+void VRDisplay::focusChanged() {
+  // TODO(mthiesse): Blur/focus the display.
+  m_vrVSyncProvider.reset();
+  if (m_navigatorVR->isFocused()) {

[jbroman, 2017/02/06 15:34:18]

nit: This check seems redundant with the one in ConnectVSyncProvider. Is it
useful to check twice?

[mthiesse, 2017/02/06 16:37:47]

Removed redundant check.

+    ConnectVSyncProvider();
+  }
+}
+
 DEFINE_TRACE(VRDisplay) {
   EventTargetWithInlineData::trace(visitor);
   ContextLifecycleObserver::trace(visitor);
   visitor->trace(m_navigatorVR);
   visitor->trace(m_capabilities);
   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