Move Mouse.Sensitivity.[Changed/Started] from internal to public repo

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 4171 matching lines @@
 
 <histogram name="MemoryAndroid.NotificationForeground"
     enum="AndroidMemoryNotificationForeground">
   <summary>
     Memory notifications delivered through system callbacks to Chrome while in
     the foreground - we count LowMemory notification vs particular levels of
     TrimMemory foreground notification.
   </summary>
 </histogram>
 
+<histogram name="Mouse.Sensitivity.Changed" enum="PointerSensitivity">
+  <summary>Tracks mouse sensitivity setting.</summary>
+</histogram>
+
+<histogram name="Mouse.Sensitivity.Started" enum="PointerSensitivity">
+  <summary>Tracks mouse sensitivity setting on startup.</summary>
+</histogram>
+
 <histogram name="MouseEventPrefetch.MouseDownDuration_Click" units="ms">
   <summary>
     Measures the time elapsed between when the user mousedown-ed a link and when
     the user clicked a link.
   </summary>
 </histogram>
 
 <histogram name="MouseEventPrefetch.MouseDownFollowedByClick"
     enum="MouseEventFollowedByClick">
   <summary>
@@ skipping 15724 matching lines @@
   <group name="Disabled" label="Neither extra webstore link is visible"/>
   <group name="FooterLink" label="Link in bottom right of footer"/>
   <group name="PlusIcon" label="Plus icon in apps page"/>
   <affected-histogram name="Extensions.AppLaunch"/>
   <affected-histogram name="NewTabPage.DefaultPageType"/>
 </fieldtrial>
 
 </fieldtrials>
 
 </histogram-configuration>