Add support for cancellation of demuxer reads.

media/blink/multibuffer_data_source.h

Index: media/blink/multibuffer_data_source.h
diff --git a/media/blink/multibuffer_data_source.h b/media/blink/multibuffer_data_source.h
index c6ace437d74eafe3950e419f4d409d1b9322bb1d..acbca2fe27ce96ad57c523b8a87a863bdd104815 100644
--- a/media/blink/multibuffer_data_source.h
+++ b/media/blink/multibuffer_data_source.h
@@ -97,13 +97,6 @@ class MEDIA_BLINK_EXPORT MultibufferDataSource : public DataSource {
   // Returns true if the media resource passed a CORS access control check.
   bool DidPassCORSAccessCheck() const;
 
-  // Cancels initialization, any pending loaders, and any pending read calls
-  // from the demuxer. The caller is expected to release its reference to this
-  // object and never call it again.
-  //
-  // Method called on the render thread.
-  void Abort();
-
   // Notifies changes in playback state for controlling media buffering
   // behavior.
   void MediaPlaybackRateChanged(double playback_rate);
@@ -127,6 +120,7 @@ class MEDIA_BLINK_EXPORT MultibufferDataSource : public DataSource {
   // DataSource implementation.
   // Called from demuxer thread.
   void Stop() override;
+  void Abort() override;
 
   void Read(int64_t position,
             int size,