Revert "Revert 285479 "Make DataSource::Stop() synchronous.""

chrome/utility/media_galleries/ipc_data_source.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 CHROME_UTILITY_MEDIA_GALLERIES_IPC_DATA_SOURCE_H_
 #define CHROME_UTILITY_MEDIA_GALLERIES_IPC_DATA_SOURCE_H_
 
 #include <map>
 #include <string>
 
@@ skipping 14 matching lines @@
 // for read operations to succeed.
 class IPCDataSource: public media::DataSource,
                      public UtilityMessageHandler {
  public:
   // May only be called on the utility thread.
   explicit IPCDataSource(int64 total_size);
   virtual ~IPCDataSource();
 
   // Implementation of DataSource. These methods may be called on any single
   // thread. First usage of these methods attaches a thread checker.
-  virtual void Stop(const base::Closure& callback) OVERRIDE;
+  virtual void Stop() OVERRIDE;
   virtual void Read(int64 position, int size, uint8* data,
                     const ReadCB& read_cb) OVERRIDE;
   virtual bool GetSize(int64* size_out) OVERRIDE;
   virtual bool IsStreaming() OVERRIDE;
   virtual void SetBitrate(int bitrate) OVERRIDE;
 
   // Implementation of UtilityMessageHandler. May only be called on the utility
   // thread.
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
 
@@ skipping 19 matching lines @@
 
   base::ThreadChecker utility_thread_checker_;
 
   // Enforces that the DataSource methods are called on one other thread only.
   base::ThreadChecker data_source_thread_checker_;
 };
 
 }  // namespace metadata
 
 #endif  // CHROME_UTILITY_MEDIA_GALLERIES_IPC_DATA_SOURCE_H_