Add a RAPPOR metric to track where users click to allow mixed scripts.

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 125 matching lines @@
 </rappor-metric>
 
 <rappor-metric name="ContentSettings.MixedScript.RanMixedScript"
     type="ETLD_PLUS_ONE">
   <owner>lgarron@chromium.org</owner>
   <summary>
     The eTLD+1 of a URL that when mixed script actually ran.
   </summary>
 </rappor-metric>
 
+<rappor-metric name="ContentSettings.MixedScript.UserClickedAllow"
+    type="ETLD_PLUS_ONE">
+  <owner>lgarron@chromium.org</owner>
+  <summary>
+    The eTLD+1 of a URL where the user clicked &quot;Load unsafe scripts&quot;
+    on a mixed content shield. (This results in a page refresh. Mixed scripts
+    may not actually run until the users triggers them again after the refresh.)
+  </summary>
+</rappor-metric>
+
 <rappor-metric name="ContentSettings.PermissionActions_Camera.Revoked.Url"
     type="ETLD_PLUS_ONE">
   <owner>jialiul@chromium.org</owner>
   <summary>
     The domain for which a camera permission was revoked.
   </summary>
 </rappor-metric>
 
 <rappor-metric name="ContentSettings.PermissionActions_Geolocation.Denied.Url"
     type="ETLD_PLUS_ONE">
@@ skipping 298 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>