Mojo-ify implementation of screen orientation locking/unlocking.

content/public/common/screen_orientation.mojom

+// 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.                                                      
+                                                                                   
+module content.mojom;
+                                                                                   
+enum ScreenOrientationLockResult {                                                 
+  // The lock was successfully applied.                                            
+  SCREEN_ORIENTATION_LOCK_RESULT_SUCCESS,                                          
+                                                                                   
+  // Failed because locking isn't available on the platform.                       
+  SCREEN_ORIENTATION_LOCK_RESULT_ERROR_NOT_AVAILABLE,                              
+                                                                                   
+  // Failed because fullscreen is required to lock.                                
+  SCREEN_ORIENTATION_LOCK_RESULT_ERROR_FULLSCREEN_REQUIRED,                        
+                                                                                   
+  // Failed because another lock/unlock got called before that one ended.          
+  SCREEN_ORIENTATION_LOCK_RESULT_ERROR_CANCELED,                                   
+};                                                                                 
+                                                                                   
+enum ScreenOrientationLockType {                                                   
+  DEFAULT = 0, // Equivalent to unlock.                                            
+  PORTRAIT_PRIMARY,                                                                 
+  PORTRAIT_SECONDARY,                                                              
+  LANDSCAPE_PRIMARY,                                                               
+  LANDSCAPE_SECONDARY,                                                             
+  ANY,                                                                             
+  LANDSCAPE,                                                                       
+  PORTRAIT,                                                                        
+  NATURAL,                                                                         
+};