Create OpenClose browser test for TaskManager with necessary refactoring....

chrome/browser/task_manager.h

Index: chrome/browser/task_manager.h
===================================================================
--- chrome/browser/task_manager.h	(revision 16479)
+++ chrome/browser/task_manager.h	(working copy)
@@ -95,8 +95,8 @@
   // moved to the front.
   static void Open();
 
-  // Close the task manager.
-  void Close();
+  // Close the task manager if it's currently opened.
+  static void Close();
 
   // Do the cleanup that can't be done during singleton destruction by
   // AtExitManager. Does nothing if the TaskManager hasn't been initialized.
@@ -122,6 +122,8 @@
   void AddResource(Resource* resource);
   void RemoveResource(Resource* resource);
 
+  void OnWindowClosed();
+
  private:
   FRIEND_TEST(TaskManagerTest, Basic);
   FRIEND_TEST(TaskManagerTest, Resources);
@@ -361,6 +363,7 @@
   virtual void GetFocused(std::vector<int>* focused) = 0;
 
   virtual void OpenWindow() = 0;
+  virtual void CloseWindow() = 0;
 };
 
 #endif  // CHROME_BROWSER_TASK_MANAGER_H_