tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index ca6b8c62374959355279357142603ea2a58786d2..f11ab9c332916f91c45cfb23a0af683d1a6fc368 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -18944,6 +18944,49 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Media.Audio.Capture.FramesProvided" units="frames">
+  <owner>grunell@chromium.org</owner>
+  <summary>
+    The number of captured audio frames that is provided by the operating system
+    in each callback, if the number is different from the desired number of
+    frames that we told the operating system about when opening the capture

[Mark P, 2016/02/29 23:41:37]

nit: omit "about"

[Henrik Grunell, 2016/03/01 17:46:24]

Done.

+    stream. Typically, Chrome will want to use a 10 ms buffer (e.g. 480 frames
+    for a sample rate of 48 kHz), but the OS may decide to capture e.g. 256
+    frames of audio at a time. If the desired frame size is used, this value
+    will be 0. This histogram then shows how frequent it is and what number of

[Mark P, 2016/02/29 23:41:37]

"frequent it is"
I can't figure out what "it" refers to.  Use of desired frame size?

[Mark P, 2016/02/29 23:41:37]

I don't understand why this value will be 0 if the desired frame size is used.
Earlier you say that we only record this histogram if the number if different
than the desired number of frames.
Which is it?

[Henrik Grunell, 2016/03/01 17:46:24]

Right, it's always recorded. Rewrote a bit.

[Henrik Grunell, 2016/03/01 17:46:24]

Yes, updated.

+    frames are used in practice. This value is logged when an audio input stream
+    is closed.

[Mark P, 2016/02/29 23:41:37]

This final sentence contradicts the implication in the first.  Do you mean that
every time you get frames, you record a local variable saying what you requested
and what you got, and you accumulate that into a list, and then when the audio
input stream is closed, you write out all those values to the histogram?  I
doubt that.  Please clarify the description.

[Henrik Grunell, 2016/03/01 17:46:24]

Clarified.

+  </summary>
+</histogram>
+
+<histogram name="Media.Audio.Capture.Glitches" units="glitches">
+  <owner>grunell@chromium.org</owner>
+  <summary>
+    The number of glitches that were detected at the OS level while an audio
+    stream was active. A glitch is detected if the OS has to skip providing a
+    set of frames. This value is logged when an audio input stream is closed.
+  </summary>
+</histogram>
+
+<histogram name="Media.Audio.Capture.LargestGlitchMs" units="ms">
+  <owner>grunell@chromium.org</owner>
+  <summary>
+    The length in milliseconds of the largest audio glitch that was detected at
+    the OS level. This value is logged when an audio input stream that has
+    suffered glitches is stopped.

[Mark P, 2016/02/29 23:41:37]

Given that I asked about the stopped versus closed difference before, I assume
this "stopped" is different than the earlier "closed".  Can you please explain
or correct?
ditto below

[Henrik Grunell, 2016/03/01 17:46:24]

Done.

+  </summary>
+</histogram>
+
+<histogram name="Media.Audio.Capture.LostFramesInMs" units="ms">
+  <owner>grunell@chromium.org</owner>
+  <summary>
+    The combined length in milliseconds of audio glitches. This is useful to

[Mark P, 2016/02/29 23:41:37]

Is this only for OS glitches like the others, or is this all types of glitches?
If it's also OS glitches, you should say so.
If it's not, you should make this histogram name different enough so it's no
likely to be compared / confused with the others.

[Henrik Grunell, 2016/03/01 17:46:24]

Only OS glitches. Done.

+    know in particular for audio processing such as echo cancellation. This
+    value is logged when an audio input stream that has suffered glitches is
+    stopped.
+  </summary>
+</histogram>
+
 <histogram name="Media.Audio.InputBufferSizeWasChangedMac"
     enum="BooleanSuccess">
   <owner>henrika@chromium.org</owner>