Fix race condition in media Pipeline::GetMediaTime() after seeking.

media/base/pipeline_impl.h

 // Copyright (c) 2016 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_BASE_PIPELINE_IMPL_H_
 #define MEDIA_BASE_PIPELINE_IMPL_H_
 
 #include <memory>
 
 #include "base/macros.h"
@@ skipping 155 matching lines @@
   // filters.
   float volume_;
 
   // Current duration as reported by Demuxer.
   base::TimeDelta duration_;
 
   // Set by GetMediaTime(), used to prevent the current media time value as
   // reported to JavaScript from going backwards in time.
   mutable base::TimeDelta last_media_time_;
 
+  // Set by Seek(), used in place of asking the renderer for current media time
+  // while a seek is pending. Renderer's time cannot be trusted until the seek
+  // has completed.
+  base::TimeDelta seek_time_;
+
   base::ThreadChecker thread_checker_;
   base::WeakPtrFactory<PipelineImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PipelineImpl);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_PIPELINE_IMPL_H_