Reduce wait time for Windows in AudioOutputController:WaitTillDataReady()

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 2168 matching lines @@
 </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.AudioOutputControllerDataNotReady" units="ms">

[Alexei Svitkine (slow), 2013/05/29 21:25:07]

We don't usually remove histograms from this file, just mark them as obsolete
using a tag. (Since their names are used for hashing by the dashboard, to map
hashes to the correct histogram names.)

-  <summary>
-    Time spent waiting in AudioOutputController::WaitTillDataReady() if the data
-    was not initially available.
-  </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.DetectedContainer" enum="MediaContainers">
   <summary>Container used for HTML5 media.</summary>
@@ skipping 12540 matching lines @@
   <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=".">

[Alexei Svitkine (slow), 2013/05/29 21:25:07]

Hmm, I don't quite understand how this is supposed to match the histogram name
you're using in the code:

Media.AudioOutputController.WaitForDataTime

Note the extra dot.

Jim, perhaps you could review this part, I'm not very familiar with this use of
the fieldtrial entry in histograms.xml.

   <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()."/>
+  <group name="WaitForDataTime"
+      label="Measures the time waited in WaitTillDataReady() if data was not
+             initially available"/>
   <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."/>
@@ skipping 1054 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>