Add a WebLockOrientationError independant from WebLockOrientationCallback.

public/platform/WebLockOrientationCallback.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 WebLockOrientationCallback_h
 #define WebLockOrientationCallback_h
 
+#include "public/platform/WebLockOrientationError.h"
 #include "public/platform/WebScreenOrientationType.h"
 
 namespace blink {
 
 // WebScreenOrientationType is an interface to be used by the embedder in order
 // to inform Blink when a screen lock operation has succeeded or failed.
 // A success notification comes with the new orientation angle and orientation
 // type and a failure notification comes with an information about the type of
 // failure.
 class WebLockOrientationCallback {
 public:
     enum ErrorType {
         ErrorTypeNotAvailable, // If locking isn't available on the platform.
         ErrorTypeFullScreenRequired, // If fullscreen is required to lock.
         ErrorTypeCanceled, // If another lock/unlock got called before that one ended.
     };
 
     virtual ~WebLockOrientationCallback() { }
 
     virtual void onSuccess(unsigned angle, WebScreenOrientationType) = 0;
-    virtual void onError(ErrorType) = 0;
+
+    // FIXME: those methods are defined and not virtual pure to not break the
+    // embedder during the transition period.
+    virtual void onError(ErrorType) { }
+    virtual void onError(WebLockOrientationError) { }
 };
 
 } // namespace blink
 
 #endif // WebLockOrientationCallback_h