Add rappor metrics by intent source for launches from home screen.

tools/metrics/rappor/rappor.xml

 <!--
 Copyright 2015 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.
 -->
 
 <rappor-configuration>
 <!--
 This file is used to generate a comprehensive list of Chrome rappor metrics
 along with a detailed description for each histogram. See the design doc at
@@ skipping 292 matching lines @@
 
 <rappor-metric name="Launch.HomeScreen.Standalone" type="ETLD_PLUS_ONE">
   <owner>dfalcantara@chromium.org</owner>
   <summary>
     The eTLD+1 of a URL that was launched from the Android Home screen into a
     WebappActivity.  This explicitly does not count relaunches via the Android
     Recents menu.
   </summary>
 </rappor-metric>
 
+<rappor-metric name="Launch.HomeScreenSource.AddToHomeScreen"
+    type="ETLD_PLUS_ONE">
+  <owner>dominickn@chromium.org</owner>
+  <summary>
+    The eTLD+1 of a URL that was launched from the Android Home screen via an
+    intent added from an add to homescreen menu item. This explicitly does not
+    count relaunches via the Android Recents menu.
+  </summary>
+</rappor-metric>
+
+<rappor-metric name="Launch.HomeScreenSource.AppBanner" type="ETLD_PLUS_ONE">
+  <owner>dominickn@chromium.org</owner>
+  <summary>
+    The eTLD+1 of a URL that was launched from the Android Home screen via an
+    intent added from an app banner. This explicitly does not count relaunches
+    via the Android Recents menu.
+  </summary>
+</rappor-metric>
+
+<rappor-metric name="Launch.HomeScreenSource.Unknown" type="ETLD_PLUS_ONE">
+  <owner>dominickn@chromium.org</owner>
+  <summary>
+    The eTLD+1 of a URL that was launched from the Android Home screen via an
+    intent added from an unknown source. This explicitly does not count
+    relaunches via the Android Recents menu.
+  </summary>
+</rappor-metric>
+
 <rappor-metric name="Media.OriginUrl.EME" type="ETLD_PLUS_ONE">
   <owner>xhwang@chromium.org</owner>
   <summary>
     The domain and registry of the URL that uses Encrypted Media Extensions
     (EME).
   </summary>
 </rappor-metric>
 
 <rappor-metric name="Media.OriginUrl.EME.Insecure" type="ETLD_PLUS_ONE">
   <owner>xhwang@chromium.org</owner>
@@ skipping 173 matching lines @@
   <owner>nparker@chromium.org</owner>
   <summary>
     The domain+registry of a URL that triggered an SSL interstitial.     Domains
     for bad-clock warnings are not reported.
   </summary>
 </rappor-metric>
 
 </rappor-metrics>
 
 </rappor-configuration>