Isolate a presenting VR device from pages other than the one presenting.

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

 // 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.
 
 #ifndef VRDisplay_h
 #define VRDisplay_h
 
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "core/dom/Document.h"
 #include "core/dom/FrameRequestCallback.h"
@@ skipping 66 matching lines @@
     void submitFrame();
 
     DECLARE_VIRTUAL_TRACE();
 
 protected:
     friend class VRController;
 
     VRDisplay(NavigatorVR*);
 
     void update(const device::blink::VRDisplayPtr&);
+
     void updatePose();
 
+    void beginPresent(ScriptPromiseResolver*);
+    void forceExitPresent();
+
+    void updateLayerBounds();
+
     VRController* controller();
 
 private:
     void onFullscreenCheck(TimerBase*);
 
     Member<NavigatorVR> m_navigatorVR;
     unsigned m_displayId;
     String m_displayName;
     bool m_isConnected;
     bool m_isPresenting;
     bool m_canUpdateFramePose;
     unsigned m_compositorHandle;
     Member<VRDisplayCapabilities> m_capabilities;
     Member<VRStageParameters> m_stageParameters;
     Member<VREyeParameters> m_eyeParametersLeft;
     Member<VREyeParameters> m_eyeParametersRight;
     device::blink::VRPosePtr m_framePose;
     VRLayer m_layer;
     double m_depthNear;
     double m_depthFar;
 
     Timer<VRDisplay> m_fullscreenCheckTimer;
 };
 
 using VRDisplayVector = HeapVector<Member<VRDisplay>>;
 
 } // namespace blink
 
 #endif // VRDisplay_h