Add User Actions and adding more details to UMA metrics for overscroll navigation

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 12906 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="OverrideEncoding">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
   <obsolete>Obsolete as of 08/2016</obsolete>
 </action>
 
+<action name="Overscroll_Cancelled.Back">
+  <owner>mfomitchev@chromium.org</owner>
+  <description>
+    When horizontal overscroll corresponding to the BACK navigation is cancelled
+    - either because the user performed an interfering action such as pressing a
+    key, or because the user ended the drag before the navigation threshold was
+    passed.
+  </description>
+</action>
+
+<action name="Overscroll_Cancelled.Forward">
+  <owner>mfomitchev@chromium.org</owner>
+  <description>
+    When horizontal overscroll corresponding to the FORWARD navigation is
+    cancelled - either because the user performed an interfering action such as
+    pressing a key, or because the user ended the drag before the navigation
+    threshold was passed.
+  </description>
+</action>
+
+<action name="Overscroll_Navigated.Back">
+  <owner>mfomitchev@chromium.org</owner>
+  <description>
+    When horizontal overscroll initiates a BACK navigation in the browser.
+  </description>
+</action>
+
+<action name="Overscroll_Navigated.Forward">
+  <owner>mfomitchev@chromium.org</owner>
+  <description>
+    When horizontal overscroll initiates a FORWARD navigation in the browser.
+  </description>
+</action>
+
 <action name="PDF.FitToHeightButton">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
   <obsolete>Removed with Out of Process PDF (issue 303491)</obsolete>
 </action>
 
 <action name="PDF.FitToPageButton">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
   <obsolete>Removed with Out of Process PDF (issue 303491)</obsolete>
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 <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>