Add metrics for when a cast is started or stopped from the system tray.

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 11325 matching lines @@
 
 <action name="StatusArea_Cast_Detailed">
   <owner>jdufault@chromium.org</owner>
   <description>
     Counts the number of times the user has clicked on the &quot;Cast desktop
     to&quot; status tray item and is now in the detail view to select a cast
     receiver.
   </description>
 </action>
 
+<action name="StatusArea_Cast_Detailed_Launch_Cast">
+  <owner>jdufault@chromium.org</owner>
+  <description>
+    Counts the number of times the user has initiated a cast from the system
+    tray. This does not mean the cast has actually begun, as the user still has
+    to select what to cast (ie, the desktop or a tab) and they may cancel the
+    process.
+  </description>
+</action>
+
+<action name="StatusArea_Cast_StopCast">
+  <owner>jdufault@chromium.org</owner>
+  <description>
+    Counts the number of times the user has stopped a cast from the system tray.
+  </description>
+</action>
+
 <action name="StatusArea_Drive_CancelOperation">
   <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="StatusArea_Drive_Detailed">
   <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 1103 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>