[Android] Add UMA for pull-to-refresh activation

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 7546 matching lines @@
   <description>
     User taped on the page while the preview page is being shown.
   </description>
 </action>
 
 <action name="MobilePreviewPageTabClose">
   <owner>ksimbili@chromium.org</owner>
   <description>User closes the tab while preview page is loaded.</description>
 </action>
 
+<action name="MobilePullGestureReload">
+  <owner>jdduke@chromium.org</owner>
+  <description>
+    Emitted on Android when a pull-to-refresh touch gesture initiates a page
+    reload. This fires only after the triggering touch is released while the
+    refresh effect has been pulled beyond the activation threshold.
+  </description>
+</action>
+
 <action name="MobileReceivedExternalIntent">
   <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="MobileRendererCrashed">
   <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 4244 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>