Move systemInfo.cpu API out out experimental namespace.

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 11826 matching lines @@
   <int value="451" label="LOCATION_WATCHLOCATION"/>
   <int value="452" label="LOCATION_CLEARWATCH"/>
   <int value="453" label="BLUETOOTH_ADDPROFILE"/>
   <int value="454" label="BLUETOOTH_REMOVEPROFILE"/>
   <int value="455" label="BLUETOOTH_GETPROFILES"/>
   <int value="456" label="EXPERIMENTAL_IDENTITY_REMOVECACHEDAUTHTOKEN"/>
   <int value="457" label="AUDIO_GETINFO"/>
   <int value="458" label="AUDIO_SETACTIVEDEVICES"/>
   <int value="459" label="AUDIO_SETPROPERTIES"/>
   <int value="460" label="USB_RESETDEVICE"/>
+  <int value="461" label="SYSTEMINFO_CPU_GET"/>
 </enum>
 
 <enum name="ExternalDeviceAction" type="int">
   <int value="0" label="Import to Drive"/>
   <int value="1" label="View files"/>
   <int value="2" label="View files (automatically)"/>
   <int value="3" label="Watch video"/>
   <int value="4" label="Error"/>
   <int value="5" label="Close (no action)"/>
 </enum>
@@ skipping 4774 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>