Remove locking from FFmpegDemuxerStream and associated TODOs from media code.

media/filters/decrypting_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 "media/filters/decrypting_audio_decoder.h"
 
 #include <cstdlib>
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
@@ skipping 216 matching lines @@
   state_ = kPendingDemuxerRead;
   ReadFromDemuxerStream();
 }
 
 void DecryptingAudioDecoder::ReadFromDemuxerStream() {
   DCHECK(message_loop_->BelongsToCurrentThread());
   DCHECK_EQ(state_, kPendingDemuxerRead) << state_;
   DCHECK(!read_cb_.is_null());
 
   demuxer_stream_->Read(
-      base::Bind(&DecryptingAudioDecoder::DecryptAndDecodeBuffer, this));
-}
-
-void DecryptingAudioDecoder::DecryptAndDecodeBuffer(
-    DemuxerStream::Status status,
-    const scoped_refptr<DecoderBuffer>& buffer) {
-  // In theory, we don't need to force post the task here, because we do a
-  // force task post in DeliverFrame(). Therefore, even if
-  // demuxer_stream_->Read() execute the read callback on the same execution
-  // stack we are still fine. But it looks like a force post task makes the
-  // logic more understandable and manageable, so why not?
-  message_loop_->PostTask(FROM_HERE, base::Bind(
-      &DecryptingAudioDecoder::DoDecryptAndDecodeBuffer, this, status, buffer));
+      base::Bind(&DecryptingAudioDecoder::DoDecryptAndDecodeBuffer, this));
 }
 
 void DecryptingAudioDecoder::DoDecryptAndDecodeBuffer(
     DemuxerStream::Status status,
     const scoped_refptr<DecoderBuffer>& buffer) {
+  if (!message_loop_->BelongsToCurrentThread()) {
+    message_loop_->PostTask(FROM_HERE, base::Bind(
+        &DecryptingAudioDecoder::DoDecryptAndDecodeBuffer, this,
+        status, buffer));
+    return;
+  }
+
   DVLOG(3) << "DoDecryptAndDecodeBuffer()";
-  DCHECK(message_loop_->BelongsToCurrentThread());
   DCHECK_EQ(state_, kPendingDemuxerRead) << state_;
   DCHECK(!read_cb_.is_null());
   DCHECK_EQ(buffer != NULL, status == DemuxerStream::kOk) << status;
 
   if (!reset_cb_.is_null()) {
     base::ResetAndReturn(&read_cb_).Run(kAborted, NULL);
     DoReset();
     return;
   }
 
@@ skipping 189 matching lines @@
 
 base::TimeDelta DecryptingAudioDecoder::NumberOfSamplesToDuration(
     int number_of_samples) const {
   DCHECK(samples_per_second_);
   return base::TimeDelta::FromMicroseconds(base::Time::kMicrosecondsPerSecond *
                                            number_of_samples /
                                            samples_per_second_);
 }
 
 }  // namespace media