DevTools: allow selecting and showing details for coalesced record.

Source/devtools/front_end/TimelinePanel.js

Index: Source/devtools/front_end/TimelinePanel.js
diff --git a/Source/devtools/front_end/TimelinePanel.js b/Source/devtools/front_end/TimelinePanel.js
index 449cdc2271b9a9fb05ff53aac0c057be7f04cc69..7c4e0170a3a6b823d524ccca6ad52ff44b78f79d 100644
--- a/Source/devtools/front_end/TimelinePanel.js
+++ b/Source/devtools/front_end/TimelinePanel.js
@@ -749,6 +749,7 @@ WebInspector.TimelinePanel.prototype = {
     {
         var startTime = this._windowStartTime;
         var endTime = this._windowEndTime;
+
         // Return early in case 0 selection window.
         if (startTime < 0)
             return;
@@ -841,6 +842,15 @@ WebInspector.TimelinePanel.prototype = {
         }
     },
 
+    /**
+     * @param {string} title
+     * @param {!Object} aggregatedStats
+     */
+    showAggregatedStatsInDetails: function(title, aggregatedStats)
+    {
+        this._detailsView.setContent(title, WebInspector.TimelineUIUtils.generatePieChart(aggregatedStats));
+    },
+
     __proto__: WebInspector.Panel.prototype
 }
 
@@ -945,7 +955,13 @@ WebInspector.TimelineModeViewDelegate.prototype = {
     /**
      * @param {?WebInspector.TimelineModel.Record} record
      */
-    selectRecord: function(record) {}
+    selectRecord: function(record) {},
+
+    /**
+     * @param {string} title
+     * @param {!Object} aggregatedStats
+     */
+    showAggregatedStatsInDetails: function(title, aggregatedStats) {}
 }
 
 /**