Add DecryptingDemuxerStream::Stop().

media/filters/decrypting_demuxer_stream.h

Index: media/filters/decrypting_demuxer_stream.h
diff --git a/media/filters/decrypting_demuxer_stream.h b/media/filters/decrypting_demuxer_stream.h
index 4e4cca2237497dedcd737ad14fed7aaf6e3d800a..aa9e897f226b0194492b3583cee03a5b333a1a21 100644
--- a/media/filters/decrypting_demuxer_stream.h
+++ b/media/filters/decrypting_demuxer_stream.h
@@ -36,11 +36,19 @@ class MEDIA_EXPORT DecryptingDemuxerStream : public DemuxerStream {
   void Initialize(DemuxerStream* stream,
                   const PipelineStatusCB& status_cb);
 
-  // Cancels all pending operations and fires all pending callbacks.  Sets
-  // |this| to kUninitialized state if |this| hasn't been initialized, or to
-  // kIdle state otherwise.
+  // Cancels all pending operations and fires all pending callbacks. If in
+  // kPendingDemuxerRead or kPendingDecrypt state, waits for the pending
+  // operation to finish before satisfying |closure|. Sets the state to
+  // kUninitialized if |this| hasn't been initialized, or to kIdle otherwise.
   void Reset(const base::Closure& closure);
 
+  // Cancels all pending operations immediately and fires all pending callbacks
+  // and sets the state to kStopped. Does NOT wait for any pending operations.
+  // Note: During the teardown process, media pipeline will be waiting on the
+  // render main thread. If a Decryptor depends on the render main thread
+  // (e.g. PpapiDecryptor), the pending DecryptCB would not be satisfied.
+  void Stop(const base::Closure& closure);
+
   // DemuxerStream implementation.
   virtual void Read(const ReadCB& read_cb) OVERRIDE;
   virtual AudioDecoderConfig audio_decoder_config() OVERRIDE;
@@ -60,6 +68,7 @@ class MEDIA_EXPORT DecryptingDemuxerStream : public DemuxerStream {
     kPendingDemuxerRead,
     kPendingDecrypt,
     kWaitingForKey,
+    kStopped
   };
 
   // Callback for DecryptorHost::RequestDecryptor().