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

webkit/media/crypto/ppapi/ffmpeg_cdm_audio_decoder.cc

 // 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.
 
 #include "webkit/media/crypto/ppapi/ffmpeg_cdm_audio_decoder.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "media/base/audio_bus.h"
@@ skipping 170 matching lines @@
          config.samples_per_second > 0 &&
          config.samples_per_second <= media::limits::kMaxSampleRate;
 }
 
 cdm::Status FFmpegCdmAudioDecoder::DecodeBuffer(
     const uint8_t* compressed_buffer,
     int32_t compressed_buffer_size,
     int64_t input_timestamp,
     cdm::AudioFrames* decoded_frames) {
   DVLOG(1) << "DecodeBuffer()";
-  const bool is_end_of_stream = compressed_buffer_size == 0;
+  const bool is_end_of_stream = !compressed_buffer;
   base::TimeDelta timestamp =
       base::TimeDelta::FromMicroseconds(input_timestamp);
 
   bool is_vorbis = codec_context_->codec_id == CODEC_ID_VORBIS;
   if (!is_end_of_stream) {
     if (last_input_timestamp_ == media::kNoTimestamp()) {
       if (is_vorbis && timestamp < base::TimeDelta()) {
         // Dropping frames for negative timestamps as outlined in section A.2
         // in the Vorbis spec. http://xiph.org/vorbis/doc/Vorbis_I_spec.html
         int frames_to_drop = floor(
@@ skipping 187 matching lines @@
   }
 }
 
 void FFmpegCdmAudioDecoder::SerializeInt64(int64 value) {
   int previous_size = serialized_audio_frames_.size();
   serialized_audio_frames_.resize(previous_size + sizeof(value));
   memcpy(&serialized_audio_frames_[0] + previous_size, &value, sizeof(value));
 }
 
 }  // namespace webkit_media