WebVR: avoid race conditions for partially-initialized display

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 108 matching lines @@
   void OnActivate(device::mojom::blink::VRDisplayEventReason) override;
   void OnDeactivate(device::mojom::blink::VRDisplayEventReason) override;
 
   ScriptedAnimationController& ensureScriptedAnimationController(Document*);
 
   Member<NavigatorVR> m_navigatorVR;
   unsigned m_displayId;
   String m_displayName;
   bool m_isConnected;
   bool m_isPresenting;
+  bool m_isValidDeviceForPresenting;
   bool m_canUpdateFramePose;
   Member<VRDisplayCapabilities> m_capabilities;
   Member<VRStageParameters> m_stageParameters;
   Member<VREyeParameters> m_eyeParametersLeft;
   Member<VREyeParameters> m_eyeParametersRight;
   device::mojom::blink::VRPosePtr m_framePose;
   VRLayer m_layer;
   double m_depthNear;
   double m_depthFar;
 
@@ skipping 32 matching lines @@
   ServiceInactive = 11,
   RequestDenied = 12,
   PresentationResultMax,  // Must be last member of enum.
 };
 
 void ReportPresentationResult(PresentationResult);
 
 }  // namespace blink
 
 #endif  // VRDisplay_h