add UMA metrics for voice interaction entries.

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 16825 matching lines @@
 <action name="ViewSource">
   <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="VirtualKeyboardLoaded">
   <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="VoiceInteraction.MetalayerStarted.Search_Shift_A">
+  <owner>muyuanli@chromium.org</owner>
+  <description>User launched metalayer through Search + Shift + A.</description>
+</action>
+
+<action name="VoiceInteraction.Started.AppListButtonLongPress">
+  <owner>muyuanli@chromium.org</owner>
+  <description>
+    User launched voice interaction session through long pressing app list
+    button.
+  </description>
+</action>
+
+<action name="VoiceInteraction.Started.Search_A">
+  <owner>muyuanli@chromium.org</owner>
+  <description>
+    User launched voice interaction session through Search + A.
+  </description>
+</action>
+
+<action name="VoiceInteraction.Started.Search_Space">
+  <owner>muyuanli@chromium.org</owner>
+  <description>
+    User launched voice interaction session through Search + Space.
+  </description>
+</action>
+
 <action name="WP_EditImage">
   <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="WP_Gallery">
   <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>
 
@@ skipping 446 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>