Implement WebVR presentation pausing for VR Shell Menu Mode

device/vr/android/gvr/gvr_delegate.h

Index: device/vr/android/gvr/gvr_delegate.h
diff --git a/device/vr/android/gvr/gvr_delegate.h b/device/vr/android/gvr/gvr_delegate.h
index d7b4297e97f3523fc0370dc64d2d233f51aafba0..4e721cbccc5a303ffef4f13e1defb24d0c830935 100644
--- a/device/vr/android/gvr/gvr_delegate.h
+++ b/device/vr/android/gvr/gvr_delegate.h
@@ -5,6 +5,7 @@
 #ifndef DEVICE_VR_ANDROID_GVR_DELEGATE_H
 #define DEVICE_VR_ANDROID_GVR_DELEGATE_H
 
+#include "base/memory/weak_ptr.h"
 #include "device/vr/android/gvr/gvr_device_provider.h"
 #include "device/vr/vr_export.h"
 #include "third_party/gvr-android-sdk/src/ndk/include/vr/gvr/capi/include/gvr_types.h"
@@ -34,9 +35,10 @@ class DEVICE_VR_EXPORT GvrDelegateProvider {
   static void SetInstance(GvrDelegateProvider* delegate_provider);
   static GvrDelegateProvider* GetInstance();
 
-  virtual bool RequestWebVRPresent(GvrDeviceProvider* device_provider) = 0;
+  virtual bool RequestWebVRPresent(
+      base::WeakPtr<GvrDeviceProvider> device_provider) = 0;
   virtual void ExitWebVRPresent() = 0;
-  virtual GvrDelegate* GetNonPresentingDelegate() = 0;
+  virtual base::WeakPtr<GvrDelegate> GetNonPresentingDelegate() = 0;
   virtual void DestroyNonPresentingDelegate() = 0;
 
  private: