media::BindToLoop() is born, with example uses to slim down WebMediaPlayerProxy.

webkit/media/webmediaplayer_impl.cc

Index: webkit/media/webmediaplayer_impl.cc
diff --git a/webkit/media/webmediaplayer_impl.cc b/webkit/media/webmediaplayer_impl.cc
index 706ca8411d0ec36febdc81a3acccf6874c5a5df1..3c485dab4ee8656d36c90aa44bf4b706fbe5dd23 100644
--- a/webkit/media/webmediaplayer_impl.cc
+++ b/webkit/media/webmediaplayer_impl.cc
@@ -16,6 +16,7 @@
 #include "base/string_number_conversions.h"
 #include "base/synchronization/waitable_event.h"
 #include "media/audio/null_audio_sink.h"
+#include "media/base/bind_to_loop.h"
 #include "media/base/filter_collection.h"
 #include "media/base/limits.h"
 #include "media/base/media_log.h"
@@ -90,6 +91,10 @@ COMPILE_ASSERT_MATCHING_ENUM(Anonymous);
 COMPILE_ASSERT_MATCHING_ENUM(UseCredentials);
 #undef COMPILE_ASSERT_MATCHING_ENUM
 
+#define BIND_TO_RENDER_LOOP(function) \
+  media::BindToLoop(main_loop_->message_loop_proxy(), base::Bind( \
+      function, weak_this_.GetWeakPtr()))
+
 static WebKit::WebTimeRanges ConvertToWebTimeRanges(
     const media::Ranges<base::TimeDelta>& ranges) {
   WebKit::WebTimeRanges result(ranges.size());
@@ -132,7 +137,8 @@ WebMediaPlayerImpl::WebMediaPlayerImpl(
       audio_renderer_sink_(audio_renderer_sink),
       is_local_source_(false),
       supports_save_(true),
-      decryptor_(proxy_.get(), client, frame) {
+      decryptor_(proxy_.get(), client, frame),
+      weak_this_(this) {
   media_log_->AddEvent(
       media_log_->CreateEvent(media::MediaLogEvent::WEBMEDIAPLAYER_CREATED));
 
@@ -159,7 +165,7 @@ WebMediaPlayerImpl::WebMediaPlayerImpl(
   scoped_refptr<media::VideoRendererBase> video_renderer =
       new media::VideoRendererBase(
           base::Bind(&WebMediaPlayerProxy::Repaint, proxy_),
-          base::Bind(&WebMediaPlayerProxy::SetOpaque, proxy_.get()),
+          BIND_TO_RENDER_LOOP(&WebMediaPlayerImpl::SetOpaque),
           true);
   filter_collection_->AddVideoRenderer(video_renderer);
   proxy_->set_frame_provider(video_renderer);
@@ -256,12 +262,12 @@ void WebMediaPlayerImpl::load(const WebKit::WebURL& url, CORSMode cors_mode) {
   proxy_->set_data_source(
       new BufferedDataSource(main_loop_, frame_, media_log_,
                              base::Bind(&WebMediaPlayerImpl::NotifyDownloading,
-                                        base::Unretained(this))));
+                                        weak_this_.GetWeakPtr())));
   proxy_->data_source()->Initialize(
       url, static_cast<BufferedResourceLoader::CORSMode>(cors_mode),
       base::Bind(
           &WebMediaPlayerImpl::DataSourceInitialized,
-          base::Unretained(this), gurl));
+          weak_this_.GetWeakPtr(), gurl));
 
   is_local_source_ = !gurl.SchemeIs("http") && !gurl.SchemeIs("https");
 
@@ -335,8 +341,7 @@ void WebMediaPlayerImpl::seek(float seconds) {
   // Kick off the asynchronous seek!
   pipeline_->Seek(
       seek_time,
-      base::Bind(&WebMediaPlayerProxy::PipelineSeekCallback,
-                 proxy_.get()));
+      BIND_TO_RENDER_LOOP(&WebMediaPlayerImpl::OnPipelineSeek));
 }
 
 void WebMediaPlayerImpl::setEndTime(float seconds) {
@@ -967,10 +972,9 @@ void WebMediaPlayerImpl::NotifyDownloading(bool is_downloading) {
 void WebMediaPlayerImpl::StartPipeline() {
   pipeline_->Start(
       filter_collection_.Pass(),
-      base::Bind(&WebMediaPlayerProxy::PipelineEndedCallback, proxy_.get()),
-      base::Bind(&WebMediaPlayerProxy::PipelineErrorCallback, proxy_.get()),
-      base::Bind(&WebMediaPlayerProxy::PipelineInitializationCallback,
-                 proxy_.get()));
+      BIND_TO_RENDER_LOOP(&WebMediaPlayerImpl::OnPipelineEnded),
+      BIND_TO_RENDER_LOOP(&WebMediaPlayerImpl::OnPipelineError),
+      BIND_TO_RENDER_LOOP(&WebMediaPlayerImpl::OnPipelineInitialize));
 }
 
 void WebMediaPlayerImpl::SetNetworkState(WebMediaPlayer::NetworkState state) {