GTK: A first *very* rough cut at a global menu.

chrome/browser/ui/gtk/global_menu_bar.h

+// 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.
+
+#ifndef CHROME_BROWSER_UI_GTK_GLOBAL_MENU_BAR_H_
+#define CHROME_BROWSER_UI_GTK_GLOBAL_MENU_BAR_H_
+
+#include <map>
+
+#include "chrome/browser/command_updater.h"
+#include "content/common/notification_observer.h"
+#include "content/common/notification_registrar.h"
+#include "ui/base/gtk/gtk_signal.h"
+
+class Browser;
+class BrowserWindowGtk;
+struct GlobalMenuBarCommand;
+
+typedef struct _GtkAccelGroup GtkAccelGroup;
+typedef struct _GtkWidget GtkWidget;
+
+// Controls the Mac style menu bar on Linux.
+//
+// Unity and some configurations of GNOME have a Apple-like menu bar at the top
+// of the screen that changes depending on the active window. These mainly work
+// by inspecting the application's widget hierarchy, and intercepting any
+// GtkMenuBar found. Thankfully, these systems don't check to see if the menu
+// bar itself is visible, so we insert a GtkMenuBar into the window hierarchy
+// and set it to be invisible.
+class GlobalMenuBar : public CommandUpdater::CommandObserver,
+                      public NotificationObserver {
+ public:
+  GlobalMenuBar(Browser* browser, BrowserWindowGtk* window);
+  virtual ~GlobalMenuBar();
+
+  GtkWidget* widget() { return menu_bar_; }
+
+ private:
+  typedef std::map<int, GtkWidget*> IDMenuItemMap;
+
+  // Helper function that builds the data.
+  void BuildGtkMenuFrom(int menu_str_id,
+                        std::map<int, GtkWidget*>* id_to_menu_item,
+                        GlobalMenuBarCommand* commands);
+
+  // CommandUpdater::CommandObserver:
+  virtual void EnabledStateChangedForCommand(int id, bool enabled);
+
+  // NotificationObserver:
+  virtual void Observe(NotificationType type,
+                       const NotificationSource& source,
+                       const NotificationDetails& details);
+
+  CHROMEGTK_CALLBACK_0(GlobalMenuBar, void, OnItemActivated);
+
+  Browser* browser_;
+  BrowserWindowGtk* browser_window_;
+
+  NotificationRegistrar registrar_;
+
+  // Our menu bar widget.
+  GtkWidget* menu_bar_;
+
+  // For some menu items, we want to show the accelerator, but not actually
+  // explicitly handle it. To this end we connect those menu items' accelerators
+  // to this group, but don't attach this group to any top level window.
+  GtkAccelGroup* dummy_accel_group_;
+
+  // A mapping from command ids to GtkMenuItem objects. We use this to update
+  // the enable state since we are a .
+  IDMenuItemMap id_to_menu_item_;
+
+  // gtk_check_menu_item_set_active() will call the "activate" signal. We need
+  // to block this activation while we change the checked state.
+  bool block_activation_;
+};
+
+#endif  // CHROME_BROWSER_UI_GTK_GLOBAL_MENU_BAR_H_