Cleanup: return by const reference instead of value in BufferedResourceLoader

media/blink/buffered_resource_loader.h

 // Copyright 2013 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 MEDIA_BLINK_BUFFERED_RESOURCE_LOADER_H_
 #define MEDIA_BLINK_BUFFERED_RESOURCE_LOADER_H_
 
 #include <string>
 
 #include "base/callback.h"
@@ skipping 190 matching lines @@
   // Cancels and closes any outstanding deferred ActiveLoader instances. Does
   // not report a failed state, so subsequent read calls to cache may still
   // complete okay. If the ActiveLoader is not deferred it will be canceled once
   // it is unless playback starts before then (as determined by the reported
   // playback rate).
   void CancelUponDeferral();
 
   // Returns the original URL of the response. If the request is redirected to
   // another URL it is the URL after redirected. If the response is generated in
   // a Service Worker it is empty.
-  const GURL response_original_url() const { return response_original_url_; }
+  const GURL& response_original_url() const { return response_original_url_; }
 
   // Returns an estimate of the amount of memory owned by the resource loader.
   int64_t GetMemoryUsage() const;
 
  private:
   friend class BufferedDataSourceTest;
   friend class BufferedResourceLoaderTest;
   friend class MockBufferedDataSource;
 
   // Updates the |buffer_|'s forward and backward capacities.
@@ skipping 107 matching lines @@
   scoped_refptr<MediaLog> media_log_;
 
   bool cancel_upon_deferral_;
 
   DISALLOW_COPY_AND_ASSIGN(BufferedResourceLoader);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BLINK_BUFFERED_RESOURCE_LOADER_H_