Pipeline will execute a callback whenever an run-time error has happened.

media/base/pipeline_impl.h

Index: media/base/pipeline_impl.h
===================================================================
--- media/base/pipeline_impl.h	(revision 22059)
+++ media/base/pipeline_impl.h	(working copy)
@@ -7,9 +7,9 @@
 #ifndef MEDIA_BASE_PIPELINE_IMPL_H_
 #define MEDIA_BASE_PIPELINE_IMPL_H_
 
+#include <set>
 #include <string>
 #include <vector>
-#include <set>
 
 #include "base/message_loop.h"
 #include "base/ref_counted.h"
@@ -84,6 +84,11 @@
   virtual bool IsStreaming() const;
   virtual PipelineError GetError() const;
 
+  // |error_callback_| will be executed upon an error in the pipeline. If
+  // |error_callback_| is NULL, it is ignored. The pipeline takes ownernship
+  // of |error_callback|.
+  virtual void SetPipelineErrorCallback(PipelineCallback* error_callback);
+
  private:
   // Pipeline states, as described above.
   enum State {
@@ -323,6 +328,7 @@
   // Callbacks for various pipeline operations.
   scoped_ptr<PipelineCallback> seek_callback_;
   scoped_ptr<PipelineCallback> stop_callback_;
+  scoped_ptr<PipelineCallback> error_callback_;
 
   // Vector of our filters and map maintaining the relationship between the
   // FilterType and the filter itself.