about:tracing support for TRACE_ASYNC_START/FINISH events.

chrome/browser/resources/tracing/linux_perf_importer.js

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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 Imports text files in the Linux event trace format into the
  * timeline model. This format is output both by sched_trace and by Linux's perf
  * tool.
  *
  * This importer assumes the events arrive as a string. The unit tests provide
  * examples of the trace format.
@@ skipping 173 matching lines @@
      * Imports the data in this.events_ into model_.
      */
     importEvents: function() {
       this.importCpuData();
       if (!this.alignClocks())
         return;
       this.buildPerThreadCpuSlicesFromCpuState();
     },
 
     /**
+     * Called by the TimelineModel after all other importers have imported their
+     * events.
+     */
+    finalizeImport: function() {
+    },
+
+    /**
      * Builds the cpuSlices array on each thread based on our knowledge of what
      * each Cpu is doing.  This is done only for TimelineThreads that are
      * already in the model, on the assumption that not having any traced data
      * on a thread means that it is not of interest to the user.
      */
     buildPerThreadCpuSlicesFromCpuState: function() {
       // Push the cpu slices to the threads that they run on.
       for (var cpuNumber in this.cpuStates_) {
         var cpuState = this.cpuStates_[cpuNumber];
         var cpu = cpuState.cpu;
@@ skipping 289 matching lines @@
   };
 
   tracing.TimelineModel.registerImporter(LinuxPerfImporter);
 
   return {
     LinuxPerfImporter: LinuxPerfImporter,
     _LinuxPerfImporterTestExports: TestExports
   };
 
 });