Introduce media::AudioClock::WallTimeForTimestamp().

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 33c13d23fa390253c5b81feb9a8e8cb529f348f1..45b6914d89bdcc99c7b7f46c4d53f3200d689a7c 100644
--- a/media/filters/audio_clock.h
+++ b/media/filters/audio_clock.h
@@ -84,6 +84,12 @@ class MEDIA_EXPORT AudioClock {
   base::TimeDelta TimestampSinceWriting(
       base::TimeDelta time_since_writing) const;
 
+  // Returns the amount of wall time until |timestamp| will be played by the
+  // audio hardware.
+  //
+  // |timestamp| must be within front_timestamp() and back_timestamp().
+  base::TimeDelta WallTimeForTimestamp(base::TimeDelta timestamp) const;

[DaleCurtis, 2014/09/20 00:17:12]

What do you think about TimeToPlayback(), TimeUntilAudible(), some variation
there of?  WallTimeForTimestamp just seems kind of obtuse and this class already
introduces some non-obvious concepts.

[scherkus (not reviewing), 2014/09/22 18:34:12]

picked TimeUntilPlayback()

+
   // Returns the amount of contiguous media time buffered at the head of the
   // audio hardware buffer. Silence introduced into the audio hardware buffer is
   // treated as a break in media time.