Implement lazy initialization for VrShellDelegate

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 <memory>
 
 #include "base/android/jni_weak_ref.h"
 #include "base/callback.h"
 #include "base/macros.h"
 #include "device/vr/android/gvr/gvr_delegate.h"
 
 namespace device {
 class GvrDeviceProvider;
 }
 
 namespace vr_shell {
 
 class NonPresentingGvrDelegate;
 
 class VrShellDelegate : public device::GvrDelegateProvider {
  public:
   VrShellDelegate(JNIEnv* env, jobject obj);
   ~VrShellDelegate() override;
 
+  static device::GvrDelegateProvider* CreateVrShellDelegate();
+
   static VrShellDelegate* GetNativeVrShellDelegate(JNIEnv* env,
                                                    jobject jdelegate);
 
   void SetDelegate(device::GvrDelegate* delegate, gvr_context* context);
   void RemoveDelegate();
 
   void SetPresentResult(JNIEnv* env,
                         const base::android::JavaParamRef<jobject>& obj,
                         jboolean result);
   void DisplayActivate(JNIEnv* env,
                        const base::android::JavaParamRef<jobject>& obj);
   void UpdateVSyncInterval(JNIEnv* env,
                            const base::android::JavaParamRef<jobject>& obj,
                            jlong timebase_nanos,
                            jdouble interval_seconds);
   void OnPause(JNIEnv* env, const base::android::JavaParamRef<jobject>& obj);
   void OnResume(JNIEnv* env, const base::android::JavaParamRef<jobject>& obj);
+  void Destroy(JNIEnv* env, const base::android::JavaParamRef<jobject>& obj);
   void ShowTab(int id);
   void OpenNewTab(bool incognito);
 
   device::GvrDeviceProvider* device_provider() { return device_provider_; }
   void OnVRVsyncProviderRequest(device::mojom::VRVSyncProviderRequest request);
   base::WeakPtr<VrShellDelegate> GetWeakPtr();
 
  private:
   // device::GvrDelegateProvider implementation
   void SetDeviceProvider(device::GvrDeviceProvider* device_provider) override;
@@ skipping 20 matching lines @@
   base::WeakPtrFactory<VrShellDelegate> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(VrShellDelegate);
 };
 
 bool RegisterVrShellDelegate(JNIEnv* env);
 
 }  // namespace vr_shell
 
 #endif  // CHROME_BROWSER_ANDROID_VR_SHELL_VR_SHELL_DELEGATE_H_