Add a context menu to the gtk task manager.

chrome/browser/gtk/task_manager_gtk.h

Index: chrome/browser/gtk/task_manager_gtk.h
===================================================================
--- chrome/browser/gtk/task_manager_gtk.h	(revision 19850)
+++ chrome/browser/gtk/task_manager_gtk.h	(working copy)
@@ -27,6 +27,9 @@
   static void Show();
 
  private:
+  class ContextMenuController;
+  friend class ContextMenuController;
+
   // Initializes the task manager dialog.
   void Init();
 
@@ -46,6 +49,9 @@
   // Queries the treeview for the selected rows, and kills those processes.
   void KillSelectedProcesses();
 
+  // Opens the context menu used to select the task manager columns.
+  void ShowContextMenu();
+
   // response signal handler that notifies us of dialog responses.
   static void OnResponse(GtkDialog* dialog, gint response_id,
                          TaskManagerGtk* task_manager);
@@ -54,6 +60,10 @@
   static void OnSelectionChanged(GtkTreeSelection* selection,
                                  TaskManagerGtk* task_manager);
 
+  // button-release-event handler that opens the right-click context menu.
+  static gboolean OnButtonReleaseEvent(GtkWidget* widget, GdkEventButton* event,
+                                       TaskManagerGtk* task_manager);
+
   // The task manager.
   TaskManager* task_manager_;
 
@@ -72,6 +82,9 @@
   // The number of processes in |process_list_|.
   int process_count_;
 
+  // The context menu controller.
+  scoped_ptr<ContextMenuController> menu_controller_;
+
   // An open task manager window. There can only be one open at a time. This
   // is reset to NULL when the window is closed.
   static TaskManagerGtk* instance_;