[ScreenOrientation] Fix a possible crash point in ScreenOrientationProvider.

content/browser/screen_orientation/screen_orientation.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 CONTENT_BROWSER_SCREEN_ORIENTATION_SCREEN_ORIENTATION_H
 #define CONTENT_BROWSER_SCREEN_ORIENTATION_SCREEN_ORIENTATION_H
 
-#include "base/callback.h"
 #include "base/memory/weak_ptr.h"
 #include "content/public/browser/web_contents_binding_set.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "device/screen_orientation/public/interfaces/screen_orientation.mojom.h"
 
 namespace content {
 
 class ScreenOrientationProvider;
 class WebContents;
 
 class ScreenOrientation : public device::mojom::ScreenOrientation,
                           public WebContentsObserver {
  public:
   explicit ScreenOrientation(WebContents* web_contents);
   ~ScreenOrientation() override;
 
   ScreenOrientationProvider* GetScreenOrientationProvider();
 
  private:
   // ScreenOrientation:
   void LockOrientation(blink::WebScreenOrientationLockType orientation,
                        const LockOrientationCallback& callback) override;
   void UnlockOrientation() override;
 
   // WebContentsObserver:
   void DidNavigateMainFrame(const LoadCommittedDetails& details,
                             const FrameNavigateParams& params) override;
 
-  void NotifyLockResult(device::mojom::ScreenOrientationLockResult result);
-
   std::unique_ptr<ScreenOrientationProvider> provider_;
-  LockOrientationCallback on_result_callback_;
   WebContentsFrameBindingSet<device::mojom::ScreenOrientation> bindings_;
   base::WeakPtrFactory<ScreenOrientation> weak_factory_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_SCREEN_ORIENTATION_SCREEN_ORIENTATION_H