Clean up some VrShell threading issues and remove unnecessary WeakPtr types.

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 VrShellDelegate : public device::GvrDelegateProvider {
  public:
   VrShellDelegate(JNIEnv* env, jobject obj);
   virtual ~VrShellDelegate();
 
   static VrShellDelegate* GetNativeDelegate(JNIEnv* env, jobject jdelegate);
 
-  void SetDelegate(const base::WeakPtr<device::GvrDelegate>& delegate);
+  void SetDelegate(device::GvrDelegate* delegate);
   void RemoveDelegate();
 
   void SetPresentResult(JNIEnv* env, jobject obj, jboolean result);
   void DisplayActivate(JNIEnv* env, jobject obj);
 
   void ForceExitVr();
+  device::GvrDeviceProvider* device_provider() { return device_provider_; }
 
   // device::GvrDelegateProvider implementation
-  void SetDeviceProvider(
-      base::WeakPtr<device::GvrDeviceProvider> device_provider) override;
+  void SetDeviceProvider(device::GvrDeviceProvider* device_provider) override;
   void RequestWebVRPresent(const base::Callback<void(bool)>& callback) override;
   void ExitWebVRPresent() override;
-  base::WeakPtr<device::GvrDelegate> GetNonPresentingDelegate() override;
+  device::GvrDelegate* GetNonPresentingDelegate() override;
   void DestroyNonPresentingDelegate() override;
   void SetListeningForActivate(bool listening) override;
 
  private:
   std::unique_ptr<device::GvrDelegate> non_presenting_delegate_;
   base::android::ScopedJavaGlobalRef<jobject> j_vr_shell_delegate_;
-  base::WeakPtr<device::GvrDeviceProvider> device_provider_;
-  base::WeakPtr<device::GvrDelegate> delegate_;
+  device::GvrDeviceProvider* device_provider_ = nullptr;
+  device::GvrDelegate* delegate_ = nullptr;
   base::Callback<void(bool)> present_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(VrShellDelegate);
 };
 
 bool RegisterVrShellDelegate(JNIEnv* env);
 
 }  // namespace vr_shell
 
 #endif  // CHROME_BROWSER_ANDROID_VR_SHELL_VR_SHELL_DELEGATE_H_