Prevent browser crash resulting from misbehaving WebVR renderer requesting multiple VSyncs.

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 "core/dom/Document.h"
 #include "core/dom/FrameRequestCallback.h"
 #include "core/events/EventTarget.h"
@@ skipping 118 matching lines @@
   // VRDisplayClient
   void OnChanged(device::mojom::blink::VRDisplayInfoPtr) override;
   void OnExitPresent() override;
   void OnBlur() override;
   void OnFocus() override;
   void OnActivate(device::mojom::blink::VRDisplayEventReason) override;
   void OnDeactivate(device::mojom::blink::VRDisplayEventReason) override;
 
   void OnVSync(device::mojom::blink::VRPosePtr,
                mojo::common::mojom::blink::TimeDeltaPtr,
-               int16_t frameId);
+               int16_t frameId,
+               device::mojom::blink::VRVSyncProvider::Status);
   void ConnectVSyncProvider();
 
   ScriptedAnimationController& ensureScriptedAnimationController(Document*);
 
   Member<NavigatorVR> m_navigatorVR;
   unsigned m_displayId = 0;
   String m_displayName;
   bool m_isConnected = false;
   bool m_isPresenting = false;
   bool m_isValidDeviceForPresenting = true;
@@ skipping 14 matching lines @@
   void dispose();
 
   TaskRunnerTimer<VRDisplay> m_fullscreenCheckTimer;
   String m_fullscreenOrigWidth;
   String m_fullscreenOrigHeight;
   gpu::gles2::GLES2Interface* m_contextGL = nullptr;
   Member<WebGLRenderingContextBase> m_renderingContext;
 
   Member<ScriptedAnimationController> m_scriptedAnimationController;
   bool m_pendingRaf = false;
+  bool m_pendingVsync = false;
   bool m_inAnimationFrame = false;
   bool m_displayBlurred = false;
   bool m_reenteredFullscreen = false;
   double m_timebase = -1;
 
   device::mojom::blink::VRDisplayPtr m_display;
 
   mojo::Binding<device::mojom::blink::VRDisplayClient> m_displayClientBinding;
   device::mojom::blink::VRVSyncProviderPtr m_vrVSyncProvider;
 
@@ skipping 18 matching lines @@
   RequestDenied = 12,
   FullscreenNotEnabled = 13,
   PresentationResultMax,  // Must be last member of enum.
 };
 
 void ReportPresentationResult(PresentationResult);
 
 }  // namespace blink
 
 #endif  // VRDisplay_h