Create video and audio decoder threads on demand.

media/filters/ffmpeg_video_decoder.cc

Index: media/filters/ffmpeg_video_decoder.cc
diff --git a/media/filters/ffmpeg_video_decoder.cc b/media/filters/ffmpeg_video_decoder.cc
index fe53f35c76ae9a57506190d9f1d6c48166452e50..ca512f896bfb62d24e785484f3c3d8631dbc0d67 100644
--- a/media/filters/ffmpeg_video_decoder.cc
+++ b/media/filters/ffmpeg_video_decoder.cc
@@ -12,6 +12,7 @@
 #include "media/base/filter_host.h"
 #include "media/base/limits.h"
 #include "media/base/media_switches.h"
+#include "media/base/message_loop_factory.h"
 #include "media/base/pipeline.h"
 #include "media/base/video_decoder_config.h"
 #include "media/base/video_frame.h"
@@ -51,8 +52,11 @@ static int GetThreadCount(CodecID codec_id) {
   return decode_threads;
 }
 
-FFmpegVideoDecoder::FFmpegVideoDecoder(MessageLoop* message_loop)
-    : message_loop_(message_loop),
+FFmpegVideoDecoder::FFmpegVideoDecoder(MessageLoopFactory* loop_factory,
+                                       const std::string& loop_name)
+    : message_loop_factory_(loop_factory),
+      loop_name_(loop_name),
+      message_loop_(NULL),
       state_(kUninitialized),
       codec_context_(NULL),
       av_frame_(NULL),
@@ -67,10 +71,11 @@ FFmpegVideoDecoder::~FFmpegVideoDecoder() {
 void FFmpegVideoDecoder::Initialize(DemuxerStream* demuxer_stream,
                                     const PipelineStatusCB& callback,
                                     const StatisticsCallback& stats_callback) {
-  if (MessageLoop::current() != message_loop_) {
-    message_loop_->PostTask(FROM_HERE, base::Bind(
-        &FFmpegVideoDecoder::Initialize, this,
-        make_scoped_refptr(demuxer_stream), callback, stats_callback));
+  if (MessageLoop::current() != EnsureMessageLoop()) {
+    message_loop_->PostTask(FROM_HERE,
+        base::Bind(&FFmpegVideoDecoder::Initialize, this,
+                   make_scoped_refptr(demuxer_stream), callback,
+                   stats_callback));
     return;
   }
 
@@ -125,9 +130,9 @@ void FFmpegVideoDecoder::Initialize(DemuxerStream* demuxer_stream,
 }
 
 void FFmpegVideoDecoder::Stop(const base::Closure& callback) {
-  if (MessageLoop::current() != message_loop_) {
-    message_loop_->PostTask(FROM_HERE, base::Bind(
-        &FFmpegVideoDecoder::Stop, this, callback));
+  if (MessageLoop::current() != EnsureMessageLoop()) {
+    message_loop_->PostTask(FROM_HERE,
+        base::Bind(&FFmpegVideoDecoder::Stop, this, callback));
     return;
   }
 
@@ -137,9 +142,9 @@ void FFmpegVideoDecoder::Stop(const base::Closure& callback) {
 }
 
 void FFmpegVideoDecoder::Seek(base::TimeDelta time, const FilterStatusCB& cb) {
-  if (MessageLoop::current() != message_loop_) {
-    message_loop_->PostTask(FROM_HERE, base::Bind(
-        &FFmpegVideoDecoder::Seek, this, time, cb));
+  if (MessageLoop::current() != EnsureMessageLoop()) {
+    message_loop_->PostTask(FROM_HERE,
+        base::Bind(&FFmpegVideoDecoder::Seek, this, time, cb));
     return;
   }
 
@@ -147,9 +152,9 @@ void FFmpegVideoDecoder::Seek(base::TimeDelta time, const FilterStatusCB& cb) {
 }
 
 void FFmpegVideoDecoder::Pause(const base::Closure& callback) {
-  if (MessageLoop::current() != message_loop_) {
-    message_loop_->PostTask(FROM_HERE, base::Bind(
-        &FFmpegVideoDecoder::Pause, this, callback));
+  if (MessageLoop::current() != EnsureMessageLoop()) {
+    message_loop_->PostTask(FROM_HERE,
+        base::Bind(&FFmpegVideoDecoder::Pause, this, callback));
     return;
   }
 
@@ -157,9 +162,9 @@ void FFmpegVideoDecoder::Pause(const base::Closure& callback) {
 }
 
 void FFmpegVideoDecoder::Flush(const base::Closure& callback) {
-  if (MessageLoop::current() != message_loop_) {
-    message_loop_->PostTask(FROM_HERE, base::Bind(
-        &FFmpegVideoDecoder::Flush, this, callback));
+  if (MessageLoop::current() != EnsureMessageLoop()) {
+    message_loop_->PostTask(FROM_HERE,
+        base::Bind(&FFmpegVideoDecoder::Flush, this, callback));
     return;
   }
 
@@ -171,8 +176,8 @@ void FFmpegVideoDecoder::Flush(const base::Closure& callback) {
 void FFmpegVideoDecoder::Read(const ReadCB& callback) {
   // Complete operation asynchronously on different stack of execution as per
   // the API contract of VideoDecoder::Read()
-  message_loop_->PostTask(FROM_HERE, base::Bind(
-      &FFmpegVideoDecoder::DoRead, this, callback));
+  EnsureMessageLoop()->PostTask(FROM_HERE,
+      base::Bind(&FFmpegVideoDecoder::DoRead, this, callback));
 }
 
 const gfx::Size& FFmpegVideoDecoder::natural_size() {
@@ -211,8 +216,8 @@ void FFmpegVideoDecoder::ReadFromDemuxerStream() {
 void FFmpegVideoDecoder::DecodeBuffer(const scoped_refptr<Buffer>& buffer) {
   // TODO(scherkus): fix FFmpegDemuxerStream::Read() to not execute our read
   // callback on the same execution stack so we can get rid of forced task post.
-  message_loop_->PostTask(FROM_HERE, base::Bind(
-      &FFmpegVideoDecoder::DoDecodeBuffer, this, buffer));
+  EnsureMessageLoop()->PostTask(FROM_HERE,
+      base::Bind(&FFmpegVideoDecoder::DoDecodeBuffer, this, buffer));
 }
 
 void FFmpegVideoDecoder::DoDecodeBuffer(const scoped_refptr<Buffer>& buffer) {
@@ -423,4 +428,11 @@ scoped_refptr<VideoFrame> FFmpegVideoDecoder::AllocateVideoFrame() {
                                  kNoTimestamp(), kNoTimestamp());
 }
 
+MessageLoop* FFmpegVideoDecoder::EnsureMessageLoop() {
+  if (!message_loop_)
+    message_loop_ = message_loop_factory_->GetMessageLoop(loop_name_);
+  return message_loop_;
+}
+
+
 }  // namespace media