Implement WebVR presentation pausing for VR Shell Menu Mode

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

Index: third_party/WebKit/Source/modules/vr/VRDisplay.cpp
diff --git a/third_party/WebKit/Source/modules/vr/VRDisplay.cpp b/third_party/WebKit/Source/modules/vr/VRDisplay.cpp
index 1480df6785b9b4e392e0ccdfd209e937ac9dddc1..32e4462f7e2bea19eecb27e92955cf896004bfdd 100644
--- a/third_party/WebKit/Source/modules/vr/VRDisplay.cpp
+++ b/third_party/WebKit/Source/modules/vr/VRDisplay.cpp
@@ -69,6 +69,7 @@ VRDisplay::VRDisplay(NavigatorVR* navigatorVR)
       m_depthNear(0.01),
       m_depthFar(10000.0),
       m_fullscreenCheckTimer(this, &VRDisplay::onFullscreenCheck),
+      m_contextGL(nullptr),
       m_animationCallbackRequested(false),
       m_inAnimationFrame(false) {}
 
@@ -110,6 +111,9 @@ void VRDisplay::disconnected() {
 bool VRDisplay::getFrameData(VRFrameData* frameData) {
   updatePose();
 
+  if (!m_framePose)
+    return false;
+
   if (!frameData)
     return false;
 
@@ -132,6 +136,10 @@ VRPose* VRDisplay::getPose() {
 }
 
 void VRDisplay::updatePose() {
+  if (m_displayBlurred) {
+    m_framePose = nullptr;
+    return;
+  }
   if (m_canUpdateFramePose) {
     m_framePose = controller()->getPose(m_displayId);
     if (m_isPresenting)
@@ -174,6 +182,26 @@ void VRDisplay::cancelAnimationFrame(int id) {
   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;