TaskManager: Fix for showing column selection menu on right click on the task manager list.

chrome/browser/resources/task_manager/main.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.
 
 /** @constructor */
 function TaskManager() { }
 
 cr.addSingletonGetter(TaskManager);
 
 /*
@@ skipping 247 matching lines @@
         item.setAttributeNode(this.document_.createAttribute("checked"));
       this.columnSelectContextMenu_.appendChild(item);
     }
 
     this.document_.body.appendChild(this.columnSelectContextMenu_);
     cr.ui.Menu.decorate(this.columnSelectContextMenu_);
 
     cr.ui.contextMenuHandler.addContextMenuProperty(this.table_.header);
     this.table_.header.contextMenu = this.columnSelectContextMenu_;
 
+    cr.ui.contextMenuHandler.addContextMenuProperty(this.table_.list);
+    this.table_.list.contextMenu = this.columnSelectContextMenu_;
+
     this.document_.addEventListener('command', this.onCommand_.bind(this));
     this.document_.addEventListener('canExecute',
                                     this.onCommandCanExecute_.bind(this));
 
   },
 
   initTableMenu_: function () {
     this.table_menu_commands_ = [];
     this.tableContextMenu_ = this.document_.createElement('menu');
 
@@ skipping 278 matching lines @@
   taskmanager.onTaskChange(start, length, tasks);
 }
 
 function taskRemoved(start, length) {
   // Sometimes this can get called too early.
   if (!taskmanager)
     return;
   taskmanager.onTaskRemove(start, length);
 }