Report timing statistics for audio controller methods via UMA.

tools/metrics/histograms/histograms.xml

 <!--
 Copyright 2013 The Chromium Authors. All rights reserved.
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.
 -->
 
 <!--
 This file is used to generate a comprehensive list of Chrome histograms along
 with a detailed description for each histogram.
 
@@ skipping 994 matching lines @@
   <summary>
     Time Non-IDB LevelDBEnv slept before successfully completing this operation.
     0 means success on the first try.
   </summary>
 </histogram>
 
 <histogram name="Linux.GlibcVersion" enum="LinuxGlibcVersion">
   <summary>The version of glibc used. (Linux only)</summary>
 </histogram>
 
+<histogram name="Media.AudioInputController.CloseTime" units="ms">

[jar (doing other things), 2013/05/14 01:43:57]

nit: These all look almost the same... and you can use the XML feature in this
file to wirte them very compactly.  Just define one histogram:
histogram name="Media.AudioInputController" units="ms">
  <summary>
  Measures the time taken for AudioInputController::
  </summary>
  </histogram>

Then define a FieldTrial  with separator="." and extensions containing:
"CloseTime"   "DoClose()."
"CreateTime"  "DoCreate()."
...
"PlayTime"   "DoPlay().  Technically only the worker method
AudioOutputController::PollAndStartIfDataReady()."

Take a look at <FieldTrial...> later in the file.

[DaleCurtis, 2013/05/15 01:30:31]

Done.

+  <summary>
+    Measures the time taken for AudioInputController::DoClose().
+  </summary>
+</histogram>
+
+<histogram name="Media.AudioInputController.CreateTime" units="ms">
+  <summary>
+    Measures the time taken for AudioInputController::DoCreate().
+  </summary>
+</histogram>
+
+<histogram name="Media.AudioInputController.RecordTime" units="ms">
+  <summary>
+    Measures the time taken for AudioInputController::DoRecord().
+  </summary>
+</histogram>
+
+<histogram name="Media.AudioOutputController.CloseTime" units="ms">
+  <summary>
+    Measures the time taken for AudioOutputController::DoClose().
+  </summary>
+</histogram>
+
+<histogram name="Media.AudioOutputController.CreateTime" units="ms">
+  <summary>
+    Measures the time taken for AudioOutputController::DoCreate().
+  </summary>
+</histogram>
+
+<histogram name="Media.AudioOutputController.DeviceChangeTime" units="ms">
+  <summary>
+    Measures the time taken for AudioOutputController::OnDeviceChange().
+  </summary>
+</histogram>
+
+<histogram name="Media.AudioOutputController.PauseTime" units="ms">
+  <summary>
+    Measures the time taken for AudioOutputController::DoPause().
+  </summary>
+</histogram>
+
+<histogram name="Media.AudioOutputController.PlayTime" units="ms">
+  <summary>
+    Measures the time taken for AudioOutputController::DoPlay().  Technically
+    only the worker method AudioOutputController::PollAndStartIfDataReady().
+  </summary>
+</histogram>
+
 <histogram name="Media.AudioRendererEvents" enum="AudioRendererEvents">
   <summary>Captures statistics for various AudioRendererImpl events.</summary>
 </histogram>
 
 <histogram name="Media.DetectedAudioCodec" enum="FFmpegCodecs">
   <summary>Audio codec used in HTML5 media.</summary>
 </histogram>
 
 <histogram name="Media.DetectedVideoCodec" enum="FFmpegCodecs">
   <summary>Video codec used in HTML5 media.</summary>
@@ skipping 11038 matching lines @@
 <fieldtrial name="SSLResumption">
   <group name="Resume_Handshake" label="Session Resumption"/>
   <group name="Full_Handshake" label="Full"/>
   <affected-histogram name="Net.SSL_Connection_Latency"/>
   <affected-histogram name="Net.SSL_Connection_Latency_Google"/>
 </fieldtrial>
 
 </fieldtrials>
 
 </histogram-configuration>