Implement WebVR presentation pausing for VR Shell Menu Mode

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/dom/DOMException.h"
 #include "core/dom/FrameRequestCallback.h"
 #include "core/dom/Fullscreen.h"
 #include "core/dom/ScriptedAnimationController.h"
@@ skipping 51 matching lines @@
       m_displayId(0),
       m_isConnected(false),
       m_isPresenting(false),
       m_canUpdateFramePose(true),
       m_capabilities(new VRDisplayCapabilities()),
       m_eyeParametersLeft(new VREyeParameters()),
       m_eyeParametersRight(new VREyeParameters()),
       m_depthNear(0.01),
       m_depthFar(10000.0),
       m_fullscreenCheckTimer(this, &VRDisplay::onFullscreenCheck),
+      m_contextGL(nullptr),
       m_animationCallbackRequested(false),
       m_inAnimationFrame(false) {}
 
 VRDisplay::~VRDisplay() {}
 
 VRController* VRDisplay::controller() {
   return m_navigatorVR->controller();
 }
 
 void VRDisplay::update(const device::blink::VRDisplayPtr& display) {
@@ skipping 21 matching lines @@
 }
 
 void VRDisplay::disconnected() {
   if (m_isConnected)
     m_isConnected = !m_isConnected;
 }
 
 bool VRDisplay::getFrameData(VRFrameData* frameData) {
   updatePose();
 
+  if (!m_framePose)
+    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() {
   updatePose();
 
   if (!m_framePose)
     return nullptr;
 
   VRPose* pose = VRPose::create();
   pose->setPose(m_framePose);
   return pose;
 }
 
 void VRDisplay::updatePose() {
+  if (m_displayBlurred) {
+    m_framePose = nullptr;
+    return;
+  }
   if (m_canUpdateFramePose) {
     m_framePose = controller()->getPose(m_displayId);
     if (m_isPresenting)
       m_canUpdateFramePose = false;
   }
 }
 
 void VRDisplay::resetPose() {
   controller()->resetPose(m_displayId);
 }
@@ skipping 22 matching lines @@
   callback->m_useLegacyTimeBase = false;
   return ensureScriptedAnimationController(doc).registerCallback(callback);
 }
 
 void VRDisplay::cancelAnimationFrame(int id) {
   if (!m_scriptedAnimationController)
     return;
   m_scriptedAnimationController->cancelCallback(id);
 }
 
+void VRDisplay::onDisplayBlur() {
+  Document* doc = m_navigatorVR->document();
+  if (!doc)
+    return;
+  m_displayBlurred = true;
+  doc->suspendScheduledTasks();

[dcheng, 2016/11/04 05:24:46]

Why do we want to suspend scheduled tasks? This will stop timers and other
things on the page from running.

[mthiesse, 2016/11/04 17:20:36]

I'll remove this in the next patchset. My thinking was that this page will not
be visible, and one of the reasons for the user hitting the menu button is the
page was providing a bad experience (like using too much of the system resources
and causing low framerates, leading to VR sickness), so suspending the page's
tasks would help with this.

However, I'm not sure this is the right approach, and this is not the right
change to do this in anyways. If I choose to move forward with something like
this I'll post a followup CL.

+  m_scriptedAnimationController->suspend();
+  m_navigatorVR->fireVrDisplayOnBlur(this);
+}
+
+void VRDisplay::onDisplayFocus() {
+  Document* doc = m_navigatorVR->document();
+  if (!doc)
+    return;
+  m_displayBlurred = false;
+  m_scriptedAnimationController->resume();
+  doc->resumeScheduledTasks();
+  m_navigatorVR->fireVrDisplayOnFocus(this);
+}
+
 void VRDisplay::serviceScriptedAnimations(double monotonicAnimationStartTime) {
   if (!m_scriptedAnimationController)
     return;
   AutoReset<bool> animating(&m_inAnimationFrame, true);
   m_animationCallbackRequested = false;
   m_scriptedAnimationController->serviceScriptedAnimations(
       monotonicAnimationStartTime);
 }
 
 void ReportPresentationResult(PresentationResult result) {
@@ skipping 312 matching lines @@
   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);
 }
 
 }  // namespace blink