Pass |paint_cb| through media::Renderer::Initialize().

This provides a common path for a media::Renderer implementation to paint video
frames through the render process' CC code. There are several options how this
callback could be used (or not used):
- Call |paint_cb| periodically to render normal video frames.
- Call |paint_cb| with a HOLE_FRAME during initialization and during frame size
  change to support hold punching.
- Ignore |paint_cb| if there is no video stream, or if video renderering is
  handled by the media::Renderer implementation entirely.

BUG=432796

Review URL: https://codereview.chromium.org/725573003

Cr-Commit-Position: refs/heads/master@{#304074}

4 files changed, 13 insertions, 9 deletions

diff --git a/media/mojo/services/media_renderer_apptest.cc b/media/mojo/services/media_renderer_apptest.cc
index 7c88ad8..60d3bd3 100644
--- a/media/mojo/services/media_renderer_apptest.cc
+++ b/media/mojo/services/media_renderer_apptest.cc
@@ -150,8 +150,9 @@ TEST_F(MojoRendererTest, BasicInitialize) {
   PipelineStatus expected_error(PIPELINE_OK);
   mojo_renderer_impl.Initialize(
       stream_provider(), base::MessageLoop::current()->QuitClosure(),
-      media::StatisticsCB(), base::Closure(),
-      base::Bind(&ErrorCallback, &expected_error), media::BufferingStateCB());
+      media::StatisticsCB(), media::BufferingStateCB(),
+      media::Renderer::PaintCB(), base::Closure(),
+      base::Bind(&ErrorCallback, &expected_error));
   base::MessageLoop::current()->Run();
 
   // We expect an error during initialization because MojoRendererService
diff --git a/media/mojo/services/mojo_renderer_impl.cc b/media/mojo/services/mojo_renderer_impl.cc
index 9ed903f..f93bfe1 100644
--- a/media/mojo/services/mojo_renderer_impl.cc
+++ b/media/mojo/services/mojo_renderer_impl.cc
@@ -35,13 +35,15 @@ MojoRendererImpl::~MojoRendererImpl() {
   // Connection to |remote_audio_renderer_| will error-out here.
 }
 
+// TODO(xhwang): Support |paint_cb| if needed.
 void MojoRendererImpl::Initialize(
     DemuxerStreamProvider* demuxer_stream_provider,
     const base::Closure& init_cb,
     const StatisticsCB& statistics_cb,
+    const BufferingStateCB& buffering_state_cb,
+    const PaintCB& /* paint_cb */,
     const base::Closure& ended_cb,
-    const PipelineStatusCB& error_cb,
-    const BufferingStateCB& buffering_state_cb) {
+    const PipelineStatusCB& error_cb) {
   DVLOG(1) << __FUNCTION__;
   DCHECK(task_runner_->BelongsToCurrentThread());
   DCHECK(demuxer_stream_provider);
diff --git a/media/mojo/services/mojo_renderer_impl.h b/media/mojo/services/mojo_renderer_impl.h
index 24a319b..4b033d8 100644
--- a/media/mojo/services/mojo_renderer_impl.h
+++ b/media/mojo/services/mojo_renderer_impl.h
@@ -43,9 +43,10 @@ class MojoRendererImpl : public Renderer, public mojo::MediaRendererClient {
   void Initialize(DemuxerStreamProvider* demuxer_stream_provider,
                   const base::Closure& init_cb,
                   const StatisticsCB& statistics_cb,
+                  const BufferingStateCB& buffering_state_cb,
+                  const PaintCB& paint_cb,
                   const base::Closure& ended_cb,
-                  const PipelineStatusCB& error_cb,
-                  const BufferingStateCB& buffering_state_cb) override;
+                  const PipelineStatusCB& error_cb) override;
   void Flush(const base::Closure& flush_cb) override;
   void StartPlayingFrom(base::TimeDelta time) override;
   void SetPlaybackRate(float playback_rate) override;
diff --git a/media/mojo/services/mojo_renderer_service.cc b/media/mojo/services/mojo_renderer_service.cc
index 60266c4..25a812b 100644
--- a/media/mojo/services/mojo_renderer_service.cc
+++ b/media/mojo/services/mojo_renderer_service.cc
@@ -89,7 +89,6 @@ MojoRendererService::MojoRendererService()
                            task_runner,
                            base::Bind(&LogMediaSourceError, media_log)).Pass(),
       SetDecryptorReadyCB(),
-      base::Bind(&PaintNothing),
       true,
       media_log));
 
@@ -149,9 +148,10 @@ void MojoRendererService::OnStreamReady(const mojo::Closure& callback) {
       base::Bind(
           &MojoRendererService::OnRendererInitializeDone, weak_this_, callback),
       base::Bind(&MojoRendererService::OnUpdateStatistics, weak_this_),
+      base::Bind(&MojoRendererService::OnBufferingStateChanged, weak_this_),
+      base::Bind(&PaintNothing),
       base::Bind(&MojoRendererService::OnRendererEnded, weak_this_),
-      base::Bind(&MojoRendererService::OnError, weak_this_),
-      base::Bind(&MojoRendererService::OnBufferingStateChanged, weak_this_));
+      base::Bind(&MojoRendererService::OnError, weak_this_));
 }
 
 void MojoRendererService::OnRendererInitializeDone(