Bug 1392216 - Part 4: Move drawing black layer commaneds to Compositor thread when stopping presentation; r=kip

MozReview-Commit-ID: 6YmQ9DYp79O

--HG--
extra : rebase_source : 45898a15fd2648db977647556d8cf120a67ff9d1

gfx/vr/VRDisplayHost.cpp

@@ -352,7 +352,7 @@ VRDisplayHost::SubmitFrame(VRLayerParent* aLayer,
   MessageLoop* loop = VRListenerThreadHolder::Loop();
 
   loop->PostTask(NewRunnableMethod<const uint32_t>(
-    "gfx::VRLayerParent::SubmitFrame",
+    "gfx::VRManager::NotifyVRVsync",
     vm, &VRManager::NotifyVRVsync, mDisplayInfo.mDisplayID
   ));
 #endif

gfx/vr/gfxVROculus.cpp

@@ -18,6 +18,7 @@
 #include "mozilla/Preferences.h"
 #include "mozilla/TimeStamp.h"
 #include "mozilla/gfx/DeviceManagerDx.h"
+#include "mozilla/layers/CompositorThread.h"
 #include "ipc/VRLayerParent.h"
 
 #include "mozilla/gfx/Quaternion.h"
@@ -198,6 +199,7 @@ VROculusSession::VROculusSession()
   , mInitFlags((ovrInitFlags)0)
   , mTextureSet(nullptr)
   , mPresenting(false)
+  , mDrawBlack(false)
 {
 }
 
@@ -321,8 +323,14 @@ VROculusSession::StopLib()
 }
 
 void
-VROculusSession::Refresh()
+VROculusSession::Refresh(bool aForceRefresh)
 {
+  // We are waiting for drawing the black layer command for
+  // Compositor thread. Ignore Refresh() calls from other threads.
+  if (mDrawBlack && !aForceRefresh) {
+    return;
+  }
+
   ovrInitFlags flags = (ovrInitFlags)(ovrInit_RequestVersion | ovrInit_MixedRendering);
   bool bInvisible = true;
   if (mPresenting) {
@@ -340,11 +348,25 @@ VROculusSession::Refresh()
       // While we are waiting for either the timeout or a new presentation,
       // fill the HMD with black / no layers.
       if (mSession && mTextureSet) {
+        if (!aForceRefresh) {
+          // ovr_SubmitFrame is only allowed been run at Compositor thread,
+          // so we post this task to Compositor thread and let it determine
+          // if reloading library.
+          mDrawBlack = true;
+          MessageLoop* loop = layers::CompositorThreadHolder::Loop();
+          loop->PostTask(NewRunnableMethod<bool>(
+            "gfx::VROculusSession::Refresh",
+            this,
+            &VROculusSession::Refresh, true));
+
+          return;
+        }
         ovrLayerEyeFov layer;
         memset(&layer, 0, sizeof(layer));
         layer.Header.Type = ovrLayerType_Disabled;
         ovrLayerHeader *layers = &layer.Header;
         ovr_SubmitFrame(mSession, 0, nullptr, &layers, 1);
+        mDrawBlack = false;
       }
     }
   }

gfx/vr/gfxVROculus.h

@@ -40,7 +40,7 @@ class VROculusSession
   friend class VRDisplayOculus;
 public:
   VROculusSession();
-  void Refresh();
+  void Refresh(bool aForceRefresh = false);
   bool IsTrackingReady() const;
   bool IsRenderReady() const;
   ovrSession Get();
@@ -65,6 +65,7 @@ private:
   TimeStamp mLastPresentationEnd;
   VRTelemetry mTelemetry;
   bool mPresenting;
+  bool mDrawBlack;
 
   ~VROculusSession();
   void Uninitialize(bool aUnloadLib);