DevTools: Add grouping by Activity to Timeline treeview.

third_party/WebKit/Source/devtools/front_end/timeline/TimelineProfileTree.js

Index: third_party/WebKit/Source/devtools/front_end/timeline/TimelineProfileTree.js
diff --git a/third_party/WebKit/Source/devtools/front_end/timeline/TimelineProfileTree.js b/third_party/WebKit/Source/devtools/front_end/timeline/TimelineProfileTree.js
index 6eeb31caca44b9afb9b1a4cd27fde8fd3adc8a9f..edc7deb51443c774ce4cfab5eabbdb12095fba61 100644
--- a/third_party/WebKit/Source/devtools/front_end/timeline/TimelineProfileTree.js
+++ b/third_party/WebKit/Source/devtools/front_end/timeline/TimelineProfileTree.js
@@ -218,11 +218,11 @@ WebInspector.TimelineProfileTree.eventStackFrame = function(event)
 
 /**
  * @constructor
- * @param {function(!WebInspector.TracingModel.Event):string} categoryMapper
+ * @param {{title: string, category: !WebInspector.TimelineCategory}} eventStyleMapper

[caseq, 2016/05/26 23:53:42]

wrong annotation, this is supposed to be a function, right?

  */
-WebInspector.TimelineAggregator = function(categoryMapper)
+WebInspector.TimelineAggregator = function(eventStyleMapper)
 {
-    this._categoryMapper = categoryMapper;
+    this._eventStyleMapper = eventStyleMapper;
     /** @type {!Map<string, !WebInspector.TimelineProfileTree.Node>} */
     this._groupNodes = new Map();
 }
@@ -232,6 +232,7 @@ WebInspector.TimelineAggregator = function(categoryMapper)
  */
 WebInspector.TimelineAggregator.GroupBy = {
     None: "None",
+    EventName: "EventName",
     Category: "Category",
     Domain: "Domain",
     Subdomain: "Subdomain",
@@ -336,7 +337,8 @@ WebInspector.TimelineAggregator.prototype = {
 
         switch (groupBy) {
         case WebInspector.TimelineAggregator.GroupBy.None: return null;
-        case WebInspector.TimelineAggregator.GroupBy.Category: return node => node.event ? this._categoryMapper(node.event) : "";
+        case WebInspector.TimelineAggregator.GroupBy.EventName: return node => node.event ? this._eventStyleMapper(node.event).title : "";
+        case WebInspector.TimelineAggregator.GroupBy.Category: return node => node.event ? this._eventStyleMapper(node.event).category.name : "";
         case WebInspector.TimelineAggregator.GroupBy.Subdomain: return groupByDomain.bind(null, false);
         case WebInspector.TimelineAggregator.GroupBy.Domain: return groupByDomain.bind(null, true);
         case WebInspector.TimelineAggregator.GroupBy.URL: return groupByURL;