trooper-o-matic: Add patch attempt timeline view to CQ graphs

appengine/trooper_o_matic/ui/tom-cq-graph.html

 <!--
 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.
 -->
 
 <link rel="import" href="../lib/dygraph.html">
 <link rel="import" href="../lib/log.html">
 <link rel="import" href="../model/patch-summary.html">
 <link rel="import" href="../model/patch-summary-list.html">
@@ skipping 63 matching lines @@
           underlayCallback: this._onGraphDrawUnderlay.bind(this),
         });
         // Overwrite default white legend background to be translucent.
         var legend = this.$.graphDiv.querySelector('.dygraph-legend');
         legend.style.backgroundColor = 'rgba(255, 255, 255, 0.8)';
       },
       _onGraphClick: function() {
         if (!this._dygraph || !this.graph.data.rowItemsAvailable) {
           return;
         }
-        this._patchSummaryList.list = [];
+        this._patchSummaryList.clear();
         var row = this._dygraph.getSelection();
         if (row !== -1) {
           this._loading = true;
           var self = this;
           this.graph.data.rowItems(row).then(function(rowItems) {
             self._loading = false;
-            self._patchSummaryList.list = rowItems.items.map(function(item) {
+            self._patchSummaryList.set(rowItems.begin, rowItems.end,
+                rowItems.items.map(function(item) {
               var itemValue = item[0];
               var itemRef = item[1];
               return new PatchSummary(itemValue, self.graph.itemUnit,
                   itemRef.issue, itemRef.patchset,
                   self.graph.itemAlertThreshold);
-            });
-            self._patchSummaryList.begin = rowItems.begin;
-            self._patchSummaryList.end = rowItems.end;
+            }));
           }).catch(log);
         }
       },
       _onGraphDrawUnderlay: function(context, area, dygraph) {
         var self = this;
         Object.keys(this.graph.alerts, function(col, threshold) {
           self.graph.breachedItems(col, threshold).then(function(items) {
             context.strokeStyle = 'red';
             context.lineWidth = 5;
             context.lineCap = 'round';
@@ skipping 20 matching lines @@
         var unit = this.graph.unit;
         Object.keys(this.graph.alerts, function(col, threshold) {
           items.push('{1} ≥ {2} {3}'.assign(col, threshold, unit));
         });
         return items.join(', ');
       },
     });
     })();
   </script>
 </polymer-element>