Added reference counting to the Pipeline interface.

media/base/pipeline.h

 // Copyright (c) 2009 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.
 
 // The pipeline is the public API clients use for playing back media.  Clients
 // provide a filter factory containing the filters they want the pipeline to
 // use to render media.
 
 #ifndef MEDIA_BASE_PIPELINE_H_
 #define MEDIA_BASE_PIPELINE_H_
@@ skipping 30 matching lines @@
   DEMUXER_ERROR_COULD_NOT_OPEN,
   DEMUXER_ERROR_COULD_NOT_PARSE,
   DEMUXER_ERROR_NO_SUPPORTED_STREAMS,
   DEMUXER_ERROR_COULD_NOT_CREATE_THREAD,
 };
 
 // Client-provided callbacks for various pipeline operations.  Clients should
 // inspect the Pipeline for errors.
 typedef Callback0::Type PipelineCallback;
 
-class Pipeline {
+class Pipeline : public base::RefCountedThreadSafe<Pipeline> {
  public:
   // Build a pipeline to render the given URL using the given filter factory to
   // construct a filter chain.  Returns true if successful, false otherwise
   // (i.e., pipeline already started).  Note that a return value of true
   // only indicates that the initialization process has started successfully.
   // Pipeline initialization is an inherently asynchronous process.  Clients can
   // either poll the IsInitialized() method (discouraged) or use the
   // |start_callback| as described below.
   //
   // This method is asynchronous and can execute a callback when completed.
@@ skipping 84 matching lines @@
 
   // Gets the size of the video output in pixel units.  If there is no video
   // or the video has not been rendered yet, the width and height will be 0.
   virtual void GetVideoSize(size_t* width_out, size_t* height_out) const = 0;
 
   // Gets the current error status for the pipeline.  If the pipeline is
   // operating correctly, this will return OK.
   virtual PipelineError GetError() const = 0;
 
  protected:
+  // Only allow ourselves to be deleted by reference counting.
+  friend class base::RefCountedThreadSafe<Pipeline>;
   virtual ~Pipeline() {}
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_PIPELINE_H_