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

device/vr/vr_device.h

Index: device/vr/vr_device.h
diff --git a/device/vr/vr_device.h b/device/vr/vr_device.h
index 6c5b0500f7b430b7f1ce1f0e6b32bd5c506dc062..862ad55952159528c0363df09a416ec073c8691b 100644
--- a/device/vr/vr_device.h
+++ b/device/vr/vr_device.h
@@ -23,22 +23,21 @@ class VRDeviceProvider;
 
 const unsigned int VR_DEVICE_LAST_ID = 0xFFFFFFFF;
 
-class VRDevice {
+class DEVICE_VR_EXPORT VRDevice {
  public:
-  DEVICE_VR_EXPORT explicit VRDevice(VRDeviceProvider* provider);
-  DEVICE_VR_EXPORT virtual ~VRDevice();
+  explicit VRDevice(VRDeviceProvider* provider);
+  virtual ~VRDevice();
 
-  DEVICE_VR_EXPORT VRDeviceProvider* provider() const { return provider_; }
-  DEVICE_VR_EXPORT unsigned int id() const { return id_; }
+  VRDeviceProvider* provider() const { return provider_; }
+  unsigned int id() const { return id_; }
 
   virtual VRDisplayPtr GetVRDevice() = 0;
   virtual VRPosePtr GetPose() = 0;
   virtual void ResetPose() = 0;
 
-  virtual void RequestPresent(){};
+  virtual bool RequestPresent();
   virtual void ExitPresent(){};
-
-  virtual void SubmitFrame(){};
+  virtual void SubmitFrame(VRPosePtr pose){};
   virtual void UpdateLayerBounds(VRLayerBoundsPtr leftBounds,
                                  VRLayerBoundsPtr rightBounds){};