Add TRACE_COUNTER support to about:tracing

chrome/browser/resources/tracing/timeline_view.js

 // Copyright (c) 2011 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.
 
 
 /**
  * @fileoverview TimelineView visualizes TRACE_EVENT events using the
  * tracing.Timeline component.
  */
 cr.define('tracing', function() {
@@ skipping 57 matching lines @@
 
       // remove old timeline
       this.timelineContainer_.textContent = '';
 
       // create new timeline if needed
       if (traceEvents.length) {
         if (this.timeline_)
           this.timeline_.detach();
         this.timeline_ = new tracing.Timeline();
         this.timeline_.model = this.timelineModel_;
+        this.timeline_.focusElement = this.parentElement;
         this.timelineContainer_.appendChild(this.timeline_);
         this.timeline_.addEventListener('selectionChange',
                                         this.onSelectionChangedBoundToThis_);
         this.onSelectionChanged_();
       } else {
         this.timeline_ = null;
       }
     },
 
     onSelectionChanged_: function(e) {
@@ skipping 87 matching lines @@
       var oldScrollTop = this.timelineContainer_.scrollTop;
       this.summaryEl_.textContent = text;
       this.timelineContainer_.scrollTop = oldScrollTop;
     }
   };
 
   return {
     TimelineView: TimelineView
   };
 });