Enforce marking "override" for functions overriding Blink.

content/renderer/media/canvas_capture_handler.h

 // Copyright 2015 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_RENDERER_MEDIA_CANVAS_CAPTURE_HANDLER_H_
 #define CONTENT_RENDERER_MEDIA_CANVAS_CAPTURE_HANDLER_H_
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 23 matching lines @@
   // Functions called by media::VideoCapturerSource implementation.
   void StartVideoCapture(
       const media::VideoCaptureParams& params,
       const media::VideoCapturerSource::VideoCaptureDeliverFrameCB&
           new_frame_callback,
       const media::VideoCapturerSource::RunningCallback& running_callback);
   void StopVideoCapture();
   blink::WebSize GetSourceSize() const { return size_; }
 
  private:
-  virtual ~CanvasCaptureHandler();
+  ~CanvasCaptureHandler() override;
 
   void CreateNewFrame(const blink::WebSkImage& image);
 
   // Implementation VideoCapturerSource that is owned by blink and delegates
   // the Start/Stop calls to CanvasCaptureHandler.
   class VideoCapturerSource;
   // Object that does all the work of running |new_frame_callback_|.
   // Destroyed on |io_task_runner_| after the class is destroyed.
   class CanvasCaptureHandlerDelegate;
 
@@ skipping 12 matching lines @@
   // Bound to the main render thread.
   base::ThreadChecker thread_checker_;
   base::WeakPtrFactory<CanvasCaptureHandler> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(CanvasCaptureHandler);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_CANVAS_CAPTURE_HANDLER_H_