Add MobileUsingMenuBy* metric actions owner and remove an unused one.

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 7520 matching lines @@
 <action name="MobileToolbarStackViewNewTab">
   <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="MobileToolbarToggleBookmark">
   <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="MobileUsingMenuByHwButtonDragging">

[Alexei Svitkine (slow), 2014/08/08 15:20:49]

Please keep this action since we have samples on it on the dashboard. (Even if
you choose to remove it from the code, it should still be kept in this file and
marked obsolete.)

[Kibeom Kim (inactive), 2014/08/08 18:29:15]

I removed HW menu dragging recently, https://codereview.chromium.org/319943003/
should we still keep this action here and mark it obsolete?

[Alexei Svitkine (slow), 2014/08/08 18:31:44]

Yes, please.

[Kibeom Kim (inactive), 2014/08/08 18:44:06]

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>
-</action>
-
 <action name="MobileUsingMenuByHwButtonTap">
-  <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>kkimlabs@chromium.org</owner>
+  <description>
+    Only for Android. Menu is shown by tapping hardware menu button.
+  </description>
 </action>
 
 <action name="MobileUsingMenuBySwButtonDragging">
-  <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>kkimlabs@chromium.org</owner>
+  <description>
+    Only for Android. Menu is shown by dragging from software menu button.
+  </description>
 </action>
 
 <action name="MobileUsingMenuBySwButtonTap">
-  <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>kkimlabs@chromium.org</owner>
+  <description>
+    Only for Android. Menu is shown by tapping software menu button.
+  </description>
 </action>
 
 <action name="MostVisited0">
   <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="MostVisited1">
   <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 3866 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>