Add documentation to the RendererConfig interface.

Whoops, forgot to add this before submitting the last patch.

BUG=410451
TEST=none

Review URL: https://codereview.chromium.org/645373005

Cr-Commit-Position: refs/heads/master@{#301971}

2 files changed, 23 insertions, 0 deletions

diff --git a/media/mojo/services/renderer_config.h b/media/mojo/services/renderer_config.h
index e64dd87..409e79c 100644
--- a/media/mojo/services/renderer_config.h
+++ b/media/mojo/services/renderer_config.h
@@ -15,21 +15,37 @@
 
 namespace media {
 
+// Interface class which clients will extend to override (at compile time) the
+// default audio or video rendering configurations for MojoRendererService.
 class PlatformRendererConfig {
  public:
   virtual ~PlatformRendererConfig() {};
 
+  // The list of audio decoders for use with the AudioRenderer.  Ownership of
+  // the decoders is passed to the caller.  The methods on each decoder will
+  // only be called on |media_task_runner|.  |media_log_cb| should be used to
+  // log errors or important status information.
   virtual ScopedVector<AudioDecoder> GetAudioDecoders(
       const scoped_refptr<base::SingleThreadTaskRunner>& media_task_runner,
       const LogCB& media_log_cb) = 0;
+
+  // The audio output sink used for rendering audio.
   virtual scoped_refptr<AudioRendererSink> GetAudioRendererSink() = 0;
+
+  // The platform's audio hardware configuration.  Note, this must remain
+  // constant for the lifetime of the PlatformRendererConfig.
   virtual const AudioHardwareConfig& GetAudioHardwareConfig() = 0;
+
+  // TODO(dalecurtis): Expose methods for retrieving the video decoders.
 };
 
 class RendererConfig {
  public:
+  // Returns an instance of the RenderConfig object.  Only one instance will
+  // exist per process.
   static RendererConfig* Get();
 
+  // Copy of the PlatformRendererConfig interface.
   ScopedVector<AudioDecoder> GetAudioDecoders(
       const scoped_refptr<base::SingleThreadTaskRunner>& media_task_runner,
       const LogCB& media_log_cb);
diff --git a/media/mojo/services/renderer_config_default.cc b/media/mojo/services/renderer_config_default.cc
index ccae590..0d7215f 100644
--- a/media/mojo/services/renderer_config_default.cc
+++ b/media/mojo/services/renderer_config_default.cc
@@ -19,12 +19,19 @@ namespace internal {
 class DefaultRendererConfig : public PlatformRendererConfig {
  public:
   DefaultRendererConfig() {
+    // TODO(dalecurtis): This will not work if the process is sandboxed...
     if (!media::IsMediaLibraryInitialized()) {
       base::FilePath module_dir;
       CHECK(PathService::Get(base::DIR_EXE, &module_dir));
       CHECK(media::InitializeMediaLibrary(module_dir));
     }
 
+    // TODO(dalecurtis): We should find a single owner per process for the audio
+    // manager or make it a lazy instance.  It's not safe to call Get()/Create()
+    // across multiple threads...
+    //
+    // TODO(dalecurtis): Eventually we'll want something other than a fake audio
+    // log factory here too.  We should probably at least DVLOG() such info.
     AudioManager* audio_manager = AudioManager::Get();
     if (!audio_manager)
       audio_manager = media::AudioManager::Create(&fake_audio_log_factory_);