Express audio delay more precisely in frames rather than milliseconds.

media/base/audio_capturer_source.h

Index: media/base/audio_capturer_source.h
diff --git a/media/base/audio_capturer_source.h b/media/base/audio_capturer_source.h
index 31b39bbf993f6367d4bfd1378426698155b286d0..fd79db3dfcd7f4ccfe3c9e711b51863dd97b133d 100644
--- a/media/base/audio_capturer_source.h
+++ b/media/base/audio_capturer_source.h
@@ -23,6 +23,8 @@ class AudioCapturerSource
   class CaptureCallback {
    public:
     // Callback to deliver the captured data from the OS.
+    // TODO(chcunningham): Update delay argument to use frames instead of
+    // milliseconds to prevent loss of precision. See http://crbug.com/587291.
     virtual void Capture(const AudioBus* audio_source,
                          int audio_delay_milliseconds,
                          double volume,