Add UMA for the new generic permisison class

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 8231 matching lines @@
 <action name="Options_DefaultImagesSettingChanged">
   <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_DefaultJavaScriptSettingChanged">
   <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_DefaultMIDISysExSettingChanged">

[Takashi Toyoshima, 2014/07/08 10:46:17]

thanks!

[Miguel Garcia, 2014/07/08 14:14:20]

Done.

-  <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
-  <description>Please enter the description of this user action.</description>
+  <owner>toyoshim@chromium.org</owner>
+  <description>
+    Triggers when the default decission for push message permissions is changed.

[Michael van Ouwerkerk, 2014/07/07 14:45:20]

Nit: s/decission/decision/

[Miguel Garcia, 2014/07/08 14:14:20]

Done.

+  </description>
 </action>
 
 <action name="Options_DefaultMediaStreamMicSettingChanged">
   <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_DefaultMediaStreamSettingChanged">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
@@ skipping 17 matching lines @@
 <action name="Options_DefaultPluginsSettingChanged">
   <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_DefaultPopupsSettingChanged">
   <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_DefaultPushMessagingSettingChanged">
+  <owner>miguelg@chromium.org</owner>
+  <description>
+    Triggers when the default decission for push message permissions is changed.

[Michael van Ouwerkerk, 2014/07/07 14:45:20]

same as above

[Miguel Garcia, 2014/07/08 14:14:20]

Done.

+  </description>
+</action>
+
 <action name="Options_DictionaryLanguage">
   <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_DisableCloudPrintProxy">
   <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 3027 matching lines @@
   <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="webapps.AddShortcut.Bookmark">
   <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>
 
 </actions>