Tighten up media::DecoderBuffer API contract for end of stream buffers (round 2).

webkit/media/crypto/ppapi/cdm_video_decoder.h

Index: webkit/media/crypto/ppapi/cdm_video_decoder.h
diff --git a/webkit/media/crypto/ppapi/cdm_video_decoder.h b/webkit/media/crypto/ppapi/cdm_video_decoder.h
index aec1f610f7362144c41afb5f8802573933e4fec6..9de1be70a55114b66ea8beef15b4e45548c13869 100644
--- a/webkit/media/crypto/ppapi/cdm_video_decoder.h
+++ b/webkit/media/crypto/ppapi/cdm_video_decoder.h
@@ -23,6 +23,9 @@ class CdmVideoDecoder {
   // returns |cdm::kSuccess| when an output frame is available. Returns
   // |cdm::kNeedMoreData| when |compressed_frame| does not produce an output
   // frame. Returns |cdm::kDecodeError| when decoding fails.
+  //
+  // A null |compressed_frame| is will attempt to flush the decoder of any
+  // remaining frames. |compressed_frame_size| and |timestamp| are ignored.
   virtual cdm::Status DecodeFrame(const uint8_t* compressed_frame,
                                   int32_t compressed_frame_size,
                                   int64_t timestamp,