Fix timestamp sent from CanvasCaptureHandler & make thread checkers clear

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 <stddef.h>
 #include <stdint.h>
 
@@ skipping 74 matching lines @@
 
   const blink::WebSize size_;
   gfx::Size last_size;
   std::vector<uint8_t> temp_data_;
   size_t row_bytes_;
   SkImageInfo image_info_;
   media::VideoFramePool frame_pool_;
 
   const scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;
   scoped_ptr<CanvasCaptureHandlerDelegate> delegate_;
-  // Bound to the main render thread.
-  base::ThreadChecker thread_checker_;
+
+  // Bound to Main Render thread.
+  base::ThreadChecker main_render_thread_checker_;
   base::WeakPtrFactory<CanvasCaptureHandler> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(CanvasCaptureHandler);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_CANVAS_CAPTURE_HANDLER_H_