[som] Add revision range exapansion.

go/src/infra/appengine/sheriff-o-matic/elements/som-extension-build-failure.html

 <link rel="import" href="/bower_components/polymer/polymer.html">
 <link rel="import" href="/bower_components/iron-ajax/iron-ajax.html">
 <link rel="import" href="/bower_components/iron-collapse/iron-collapse.html">
 <link rel="import" href="/bower_components/iron-flex-layout/classes/iron-flex-layout.html">
 <link rel="import" href="/bower_components/iron-icons/hardware-icons.html">
 <link rel="import" href="/bower_components/iron-icons/iron-icons.html">
 <link rel="import" href="/bower_components/iron-page-url/iron-page-url.html">
 <link rel="import" href="/bower_components/paper-button/paper-button.html">
 <link rel="import" href="/bower_components/paper-card/paper-card.html">
 <link rel="import" href="/bower_components/paper-drawer-panel/paper-drawer-panel.html">
 <link rel="import" href="/bower_components/paper-header-panel/paper-header-panel.html">
 <link rel="import" href="/bower_components/paper-icon-button/paper-icon-button.html">
 <link rel="import" href="/bower_components/paper-item/paper-item.html">
 <link rel="import" href="/bower_components/paper-progress/paper-progress.html">
 <link rel="import" href="/bower_components/paper-toolbar/paper-toolbar.html">
+<link rel="import" href="/elements/som-rev-range.html">
 
 <dom-module id="som-extension-build-failure">
   <template>
     <style>
      .builder {
         border-radius: 2px;
         border: 1px solid #dcdcdc;
         font-size: smaller;
         margin: .1em;
         padding: .5em;
@@ skipping 56 matching lines @@
                   </a>
                 </li>
               </template>
             </ul>
           </div>
         </template>
       </div>
       <div id="regression-ranges">
         <template is="dom-repeat" items="[[extension.regression_ranges]]" as="regressionRange" filter="_showRegressionRange">
           <div>
-            [[regressionRange.repo]]:
-            <a target="_blank" href$="[[_regressionRangeLink(regressionRange)]]">[[_regressionRange(regressionRange)]]</a>
+            <som-rev-range range="[[regressionRange]]"></som-rev-range>
           </div>
         </template>
       </div>
     </div>
   </template>
   <script>
   (function() {
     'use strict';
 
-     Polymer({
+    Polymer({
       is: 'som-extension-build-failure',
 
       properties: {
         extension: {
           type: Object,
           value: null
         },
         type: {
           type: String,
           value: ''
         },
       },
 
       _haveBuilders: function(extension) {
         return extension && extension.builders && extension.builders.length > 0;
       },
 
-     _regressionRange: function(range) {
-        if (!range.positions || range.positions.length == 0) {
-          return '';
-        }
-
-        let start = this._parseCommitPosition(range.positions[0]);
-        if (range.positions.length == 1) {
-          return start;
-        }
-
-        let end = this._parseCommitPosition(
-            range.positions[range.positions.length - 1]);
-
-        if (start && end) {
-          return `${start} - ${end}`;
-        }
-      },
-
-      _regressionRangeLink: function(range) {
-        if (!range.positions) {
-          return '';
-        }
-        let end = this._parseCommitPosition(range.positions[0]);
-        let start = end;
-        if (range.positions.length > 1) {
-          end = this._parseCommitPosition(
-              range.positions[range.positions.length - 1]);
-        }
-        return 'http://test-results.appspot.com/revision_range?start=' +
-            `${start}&end=${end}`;
-      },
-
-      _parseCommitPosition: function(pos) {
-        let groups = /refs\/heads\/master@{#([0-9]+)}/.exec(pos);
-        if (groups && groups.length == 2) {
-          return groups[1];
-        }
-      },
-
       _failureCount: function(builder) {
         // The build number range is inclusive.
         let numBuilds = builder.latest_failure - builder.first_failure + 1;
         if (numBuilds > 1) {
           return `[${numBuilds} since first detection]`;
         }
       },
 
       _classForBuilder: function(builder) {
         let classes = ['builder']
         if (this._failureCount(builder) > 1) {
           classes.push('multiple-failures');
         }
         if (this.type == 'infra-failure') {
           classes.push('infra-failure');
         }
         return classes.join(' ');
       },
 
       _showRegressionRange: function(range) {
-        return this._regressionRange(range) && range.positions.length > 0;
+        return range.positions && range.positions.length > 0;
       },
 
       _uberify: function(url) {
         let u = new URL(url);
         if (u.hostname.includes('chromium.org')) {
           u.hostname = 'uberchromegw.corp.google.com';
           u.pathname = u.pathname.replace('/p/', '/i/');
         }
         u.protocol = 'https:'
         return u.toString();
       }
     });
   })();
   </script>
 </dom-module>