Implement WebVR presentation pausing for VR Shell Menu Mode

chrome/browser/android/vr_shell/vr_shell_delegate.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 CHROME_BROWSER_ANDROID_VR_SHELL_VR_SHELL_DELEGATE_H_
 #define CHROME_BROWSER_ANDROID_VR_SHELL_VR_SHELL_DELEGATE_H_
 
 #include <jni.h>
 
 #include "base/android/jni_weak_ref.h"
 #include "base/macros.h"
 #include "device/vr/android/gvr/gvr_delegate.h"
 
+namespace device {
+class GvrDeviceProvider;
+}
+
 namespace vr_shell {
 
 class VrShell;
 
 class VrShellDelegate : public device::GvrDelegateProvider {
  public:
   VrShellDelegate(JNIEnv* env, jobject obj);
   virtual ~VrShellDelegate();
 
   static VrShellDelegate* getNativeDelegate(JNIEnv* env, jobject jdelegate);
 
+  device::GvrDeviceProvider* GetDeviceProvider() { return device_provider_; }
+
   // Called by the Java VrShellDelegate. Returns true if the GvrDeviceProvider
   // needs to handle shutdown first.
   void ExitWebVRIfNecessary(JNIEnv* env, jobject obj);
 
   // device::vrDelegateProvider implementation
   bool RequestWebVRPresent(device::GvrDeviceProvider* device_provider) override;
   void ExitWebVRPresent() override;
   device::GvrDelegate* GetNonPresentingDelegate() override;
   void DestroyNonPresentingDelegate() override;
 
   // Called from VRShell
   void OnVrShellReady(VrShell* vr_shell);
 
  private:
   std::unique_ptr<device::GvrDelegate> non_presenting_delegate_;
   base::android::ScopedJavaGlobalRef<jobject> j_vr_shell_delegate_;
   device::GvrDeviceProvider* device_provider_;
 
   DISALLOW_COPY_AND_ASSIGN(VrShellDelegate);
 };
 
 bool RegisterVrShellDelegate(JNIEnv* env);
 
 }  // namespace vr_shell
 
 #endif  // CHROME_BROWSER_ANDROID_VR_SHELL_VR_SHELL_DELEGATE_H_