Make TextRenderer::Play() a synchronous method.

This mirrors the style of API that Audio/VideoRenderer have moved
towards as well as clears the way for removing more state from Pipeline.

BUG=144683

Review URL: https://codereview.chromium.org/361293003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@281212 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 9 insertions, 36 deletions

diff --git a/media/base/pipeline.cc b/media/base/pipeline.cc
index a81e758..a393cc8 100644
--- a/media/base/pipeline.cc
+++ b/media/base/pipeline.cc
@@ -353,8 +353,7 @@ void Pipeline::StateTransitionTask(PipelineStatus status) {
 
   // Guard against accidentally clearing |pending_callbacks_| for states that
   // use it as well as states that should not be using it.
-  DCHECK_EQ(pending_callbacks_.get() != NULL,
-            (state_ == kInitPrerolling || state_ == kSeeking));
+  DCHECK_EQ(pending_callbacks_.get() != NULL, state_ == kSeeking);
 
   pending_callbacks_.reset();
 
@@ -397,7 +396,8 @@ void Pipeline::StateTransitionTask(PipelineStatus status) {
         metadata_cb_.Run(metadata);
       }
 
-      return DoInitialPreroll(done_cb);
+      // TODO(scherkus): Fold kInitPrerolling state into kPlaying.
+      return done_cb.Run(PIPELINE_OK);
 
     case kPlaying:
       base::ResetAndReturn(&seek_cb_).Run(PIPELINE_OK);
@@ -406,6 +406,8 @@ void Pipeline::StateTransitionTask(PipelineStatus status) {
         audio_renderer_->StartPlayingFrom(start_timestamp_);
       if (video_renderer_)
         video_renderer_->StartPlayingFrom(start_timestamp_);
+      if (text_renderer_)
+        text_renderer_->StartPlaying();
 
       PlaybackRateChangedTask(GetPlaybackRate());
       VolumeChangedTask(GetVolume());
@@ -426,19 +428,6 @@ void Pipeline::StateTransitionTask(PipelineStatus status) {
 //
 // That being said, deleting the renderers while keeping |pending_callbacks_|
 // running on the media thread would result in crashes.
-void Pipeline::DoInitialPreroll(const PipelineStatusCB& done_cb) {
-  DCHECK(task_runner_->BelongsToCurrentThread());
-  DCHECK(!pending_callbacks_.get());
-  SerialRunner::Queue bound_fns;
-
-  // Preroll renderers.
-  if (text_renderer_) {
-    bound_fns.Push(base::Bind(
-        &TextRenderer::Play, base::Unretained(text_renderer_.get())));
-  }
-
-  pending_callbacks_ = SerialRunner::Run(bound_fns, done_cb);
-}
 
 #if DCHECK_IS_ON
 static void VerifyBufferingStates(BufferingState* audio_buffering_state,
@@ -488,12 +477,6 @@ void Pipeline::DoSeek(
   bound_fns.Push(base::Bind(
       &Demuxer::Seek, base::Unretained(demuxer_), seek_timestamp));
 
-  // Preroll renderers.
-  if (text_renderer_) {
-    bound_fns.Push(base::Bind(
-        &TextRenderer::Play, base::Unretained(text_renderer_.get())));
-  }
-
   pending_callbacks_ = SerialRunner::Run(bound_fns, done_cb);
 }
 
diff --git a/media/base/pipeline.h b/media/base/pipeline.h
index b8307bd..f042548 100644
--- a/media/base/pipeline.h
+++ b/media/base/pipeline.h
@@ -294,10 +294,6 @@ class MEDIA_EXPORT Pipeline : public DemuxerHost {
   void OnStateTransition(PipelineStatus status);
   void StateTransitionTask(PipelineStatus status);
 
-  // Initiates an asynchronous preroll call sequence executing |done_cb|
-  // with the final status when completed.
-  void DoInitialPreroll(const PipelineStatusCB& done_cb);
-
   // Initiates an asynchronous pause-flush-seek-preroll call sequence
   // executing |done_cb| with the final status when completed.
   //
diff --git a/media/base/text_renderer.cc b/media/base/text_renderer.cc
index 6f88ef7..3a04348 100644
--- a/media/base/text_renderer.cc
+++ b/media/base/text_renderer.cc
@@ -46,7 +46,7 @@ void TextRenderer::Initialize(const base::Closure& ended_cb) {
   state_ = kPaused;
 }
 
-void TextRenderer::Play(const base::Closure& callback) {
+void TextRenderer::StartPlaying() {
   DCHECK(task_runner_->BelongsToCurrentThread());
   DCHECK_EQ(state_, kPaused) << "state_ " << state_;
 
@@ -62,7 +62,6 @@ void TextRenderer::Play(const base::Closure& callback) {
   }
 
   state_ = kPlaying;
-  callback.Run();
 }
 
 void TextRenderer::Pause(const base::Closure& callback) {
diff --git a/media/base/text_renderer.h b/media/base/text_renderer.h
index ce10912..7e719db 100644
--- a/media/base/text_renderer.h
+++ b/media/base/text_renderer.h
@@ -44,9 +44,8 @@ class MEDIA_EXPORT TextRenderer {
   // end of stream, following a play request.
   void Initialize(const base::Closure& ended_cb);
 
-  // Start text track cue decoding and rendering, executing |callback| when
-  // playback is underway.
-  void Play(const base::Closure& callback);
+  // Start text track cue decoding and rendering.
+  void StartPlaying();
 
   // Temporarily suspend decoding and rendering, executing |callback| when
   // playback has been suspended.
diff --git a/media/base/text_renderer_unittest.cc b/media/base/text_renderer_unittest.cc
index 77e8c47..2c31c92 100644
--- a/media/base/text_renderer_unittest.cc
+++ b/media/base/text_renderer_unittest.cc
@@ -184,10 +184,7 @@ class TextRendererTest : public testing::Test {
   }
 
   void Play() {
-    EXPECT_CALL(*this, OnPlay());
-    text_renderer_->Play(base::Bind(&TextRendererTest::OnPlay,
-                                    base::Unretained(this)));
-    message_loop_.RunUntilIdle();
+    text_renderer_->StartPlaying();
   }
 
   void Pause() {
@@ -215,7 +212,6 @@ class TextRendererTest : public testing::Test {
 
   MOCK_METHOD0(OnEnd, void());
   MOCK_METHOD0(OnStop, void());
-  MOCK_METHOD0(OnPlay, void());
   MOCK_METHOD0(OnPause, void());
   MOCK_METHOD0(OnFlush, void());