DevTools: Support Top-Down tree view on Timeline

Source/devtools/front_end/timeline/TimelineModel.js

Index: Source/devtools/front_end/timeline/TimelineModel.js
diff --git a/Source/devtools/front_end/timeline/TimelineModel.js b/Source/devtools/front_end/timeline/TimelineModel.js
index 51722814e375deeec817ce15a3a07a02d1a79e47..d2426980a7a5e8b964534e5b278ef4acd5cfdc98 100644
--- a/Source/devtools/front_end/timeline/TimelineModel.js
+++ b/Source/devtools/front_end/timeline/TimelineModel.js
@@ -1555,7 +1555,7 @@ WebInspector.TimelineModel.buildTopDownTree = function(events, startTime, endTim
 
 /**
  * @param {!WebInspector.TimelineModel.ProfileTreeNode} topDownTree
- * @param {function(!WebInspector.TimelineModel.ProfileTreeNode):?WebInspector.TimelineModel.ProfileTreeNode=} groupingCallback
+ * @param {?function(!WebInspector.TimelineModel.ProfileTreeNode):!WebInspector.TimelineModel.ProfileTreeNode=} groupingCallback
  * @return {!WebInspector.TimelineModel.ProfileTreeNode}
  */
 WebInspector.TimelineModel.buildBottomUpTree = function(topDownTree, groupingCallback)
@@ -1836,6 +1836,29 @@ WebInspector.InclusiveTraceEventNameFilter.prototype = {
 /**
  * @constructor
  * @implements {WebInspector.TraceEventFilter}
+ * @param {function(!WebInspector.TracingModel.Event):boolean} filter
+ */
+WebInspector.CustomFilter = function(filter)
+{
+    WebInspector.TraceEventFilter.call(this);
+    this._filter = filter;
+}
+
+WebInspector.CustomFilter.prototype = {
+    /**
+     * @override
+     * @param {!WebInspector.TracingModel.Event} event
+     * @return {boolean}
+     */
+    accept: function(event)
+    {
+        return this._filter(event);
+    }
+}
+
+/**
+ * @constructor
+ * @implements {WebInspector.TraceEventFilter}
  */
 WebInspector.ExcludeTopLevelFilter = function()
 {