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 1075 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" units="ms">
+  <summary>Measures the time taken for AudioInputController::</summary>
+</histogram>
+
+<histogram name="Media.AudioOutputController" units="ms">
+  <summary>Measures the time taken for AudioOutputController::</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 10728 matching lines @@
 <fieldtrial name="LevelDBEnvRetryTimes" separator="">
   <obsolete>
     Deprecated 2013-04 in favor of LevelDBEnvExponentialRetryTimes.
   </obsolete>
   <group name="Rename" label="RenameFile"/>
   <group name="LockFile" label="LockFile"/>
   <affected-histogram name="LevelDBEnv.IDB.TimeTo"/>
   <affected-histogram name="LevelDBEnv.TimeTo"/>
 </fieldtrial>
 
+<fieldtrial name="MediaAudioInputControllerTime" separator=".">
+  <group name="CloseTime" label="Measures the time taken for DoClose()."/>
+  <group name="CreateTime" label="Measures the time taken for DoCreate()."/>
+  <group name="RecordTime" label="Measures the time taken for DoRecord()."/>
+  <affected-histogram name="Media.AudioInputController"/>
+</fieldtrial>
+
+<fieldtrial name="MediaAudioOutputControllerTime" separator=".">
+  <group name="CloseTime" label="Measures the time taken for DoClose()."/>
+  <group name="CreateTime" label="Measures the time taken for DoCreate()."/>
+  <group name="DeviceChangeTime"
+      label="Measures the time taken for OnDeviceChange()."/>
+  <group name="PauseTime" label="Measures the time taken for DoPause()."/>
+  <group name="PlayTime"
+      label="Measures the time taken for DoPlay(). Technically only the
+             worker method AudioOutputController::PollAndStartIfDataReady()."/>
+  <affected-histogram name="Media.AudioOutputController"/>
+</fieldtrial>
+
 <fieldtrial name="NetConnectivity" separator=".">
   <group name="53.100B" label="100 bytes of data on port 53."/>
   <group name="53.100B.NoProxy"
       label="100 bytes of data on port 53 with no proxy."/>
   <group name="53.1K" label="1K bytes of data on port 53."/>
   <group name="53.1K.NoProxy"
       label="1K bytes of data on port 53 with no proxy."/>
   <group name="53.100B.RTT" label="100 bytes of data on port 53 successfully."/>
   <group name="53.100B.RTT.NoProxy"
       label="100 bytes of data on port 53 successfully with no proxy."/>
@@ skipping 995 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>