[ScreenOrientation] Fix a possible crash point in ScreenOrientationProvider.

content/public/browser/screen_orientation_provider.h

 // Copyright 2014 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_PUBLIC_BROWSER_SCREEN_ORIENTATION_PROVIDER_H_
 #define CONTENT_PUBLIC_BROWSER_SCREEN_ORIENTATION_PROVIDER_H_
 
 #include <memory>
 
 #include "base/callback.h"
@@ skipping 54 matching lines @@
   bool LockMatchesCurrentOrientation(blink::WebScreenOrientationLockType lock);
 
   // Not owned, responsible for platform implementations.
   static ScreenOrientationDelegate* delegate_;
 
   // Whether the ScreenOrientationProvider currently has a lock applied.
   bool lock_applied_;
 
   // Locks that require orientation changes are not completed until
   // OnOrientationChange.
-
   base::Optional<blink::WebScreenOrientationLockType> pending_lock_orientation_;
 
   LockOrientationCallback on_result_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(ScreenOrientationProvider);
 };
 
 } // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_SCREEN_ORIENTATION_PROVIDER_H_