Have AudioRendererImpl advance time until it's told to stop.

media/filters/audio_clock.h

Index: media/filters/audio_clock.h
diff --git a/media/filters/audio_clock.h b/media/filters/audio_clock.h
index 1a27dee00092dea9134950f7ba5b97c83c6951b5..cafe7b3aa1f738f9f652fd915c7b0a71e2e63a3c 100644
--- a/media/filters/audio_clock.h
+++ b/media/filters/audio_clock.h
@@ -29,12 +29,18 @@ class MEDIA_EXPORT AudioClock {
                   int delay_frames,
                   float playback_rate);
 
-  // Calculates the current media timestamp taking silence and changes in
+  // Returns the current media timestamp taking silence and changes in
   // playback rate into account.
   base::TimeDelta current_media_timestamp() const {
     return current_media_timestamp_;
   }
 
+  // Returns the latest media timestamp taking silence and changes in

[DaleCurtis, 2014/08/29 20:17:23]

The difference between current and latest isn't really clear here. Can you write
some more docs?

+  // playback rate into account.

[xhwang, 2014/08/29 20:45:48]

Only by looking at the comments, I have no idea what's the difference b/w the
"current" and the "latest" media timestamp...

[scherkus (not reviewing), 2014/08/30 00:24:12]

Ah I guess I used "latest" in the sense of "furthest away from now/current", but
I can see how they are synonyms.

Some ideas:
1) {front,back}_media_timestamp() (sorta matches STL)
2) current_media_timestamp() -> now() ? (sorta matches the "clock/time" aspect
of this class)
3) {earliest,latest}_media_timestamp() (like #1, except more time-based)

+  base::TimeDelta latest_media_timestamp() const {
+    return latest_media_timestamp_;
+  }
+
   // Clients can provide |time_since_writing| to simulate the passage of time
   // since last writing audio to get a more accurate current media timestamp.
   base::TimeDelta CurrentMediaTimestampSinceWriting(
@@ -53,10 +59,6 @@ class MEDIA_EXPORT AudioClock {
     return contiguous_audio_data_buffered_at_same_rate_;
   }
 
-  // Returns true if there is any audio data buffered by the audio hardware,
-  // even if there is silence mixed in.
-  bool audio_data_buffered() const { return audio_data_buffered_; }
-
  private:
   // Even with a ridiculously high sample rate of 256kHz, using 64 bits will
   // permit tracking up to 416999965 days worth of time (that's 1141 millenia).
@@ -82,9 +84,9 @@ class MEDIA_EXPORT AudioClock {
   int64_t total_buffered_frames_;
 
   base::TimeDelta current_media_timestamp_;
+  base::TimeDelta latest_media_timestamp_;
 
   // Cached results of last call to WroteAudio().
-  bool audio_data_buffered_;
   base::TimeDelta contiguous_audio_data_buffered_;
   base::TimeDelta contiguous_audio_data_buffered_at_same_rate_;