Added reference counting to the Pipeline interface.

media/base/pipeline.h

Index: media/base/pipeline.h
diff --git a/media/base/pipeline.h b/media/base/pipeline.h
index 83e30ef54185bf2df7dcdab78dcfe1120fcd10d3..58de36baac745dd742e7d3eb4d106c8333cfb74d 100644
--- a/media/base/pipeline.h
+++ b/media/base/pipeline.h
@@ -48,7 +48,7 @@ enum PipelineError {
 // 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
@@ -153,6 +153,8 @@ class Pipeline {
   virtual PipelineError GetError() const = 0;
 
  protected:
+  // Only allow ourselves to be deleted by reference counting.
+  friend class base::RefCountedThreadSafe<Pipeline>;
   virtual ~Pipeline() {}
 };