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

webkit/media/crypto/ppapi/cdm_video_decoder.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef WEBKIT_MEDIA_CRYPTO_PPAPI_CDM_VIDEO_DECODER_H_
 #define WEBKIT_MEDIA_CRYPTO_PPAPI_CDM_VIDEO_DECODER_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "webkit/media/crypto/ppapi/cdm/content_decryption_module.h"
 
 namespace webkit_media {
 
 class CdmVideoDecoder {
  public:
   virtual ~CdmVideoDecoder() {}
   virtual bool Initialize(const cdm::VideoDecoderConfig& config) = 0;
   virtual void Deinitialize() = 0;
   virtual void Reset() = 0;
   virtual bool is_initialized() const = 0;
 
   // Decodes |compressed_frame|. Stores output frame in |decoded_frame| and
   // 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| 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,
                                   cdm::VideoFrame* decoded_frame) = 0;
 };
 
 // Initializes appropriate video decoder based on GYP flags and the value of
 // |config.codec|. Returns a scoped_ptr containing a non-null initialized
 // CdmVideoDecoder* upon success.
 scoped_ptr<CdmVideoDecoder> CreateVideoDecoder(
     cdm::Allocator* allocator,
     const cdm::VideoDecoderConfig& config);
 
 }  // namespace webkit_media
 
 #endif  // WEBKIT_MEDIA_CRYPTO_PPAPI_CDM_VIDEO_DECODER_H_