Add About metric to actions.xml

tools/metrics/actions/actions.xml

 <!--
 Copyright 2014 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 a comprehensive list of Chrome user actions along with the owner
 and description for each user action.
 
@@ skipping 8259 matching lines @@
 <action name="OpenSystemOptionsDialog">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
 <action name="OpenTabpose">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
+<action name="Options_About">
+  <owner>michaelpg@chromium.org</owner>
+  <description>Settings: About Chrome</description>
+</action>
+
 <action name="Options_AccessibilityHighContrastMode">
   <owner>stevenjb@chromium.org</owner>
   <description>Settings: Accessibility: Toggle high contrast mode</description>
 </action>
 
 <action name="Options_AccessibilityHighContrastMode_Disable">
   <owner>stevenjb@chromium.org</owner>
   <description>Settings: Accessibility: Disable high contrast mode</description>
 </action>
 
@@ skipping 3763 matching lines @@
 <action name="webapps.AddShortcut.Manifest">
   <owner>mlamouri@chromium.org</owner>
   <description>
     Shortcut added to the homescreen with a valid Manifest. This action will be
     recorded in addition to AppShortcut, AppShortcutApple and Bookmark actions
     to keep a trend of whether the webapp also add meta tags.
   </description>
 </action>
 
 </actions>