Gtk3 ui: Add libgtk3ui as a separate build component

chrome/browser/ui/libgtkui/menu_util.cc

 // Copyright 2013 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.
 
-#include "chrome/browser/ui/libgtk2ui/menu_util.h"
+#include "chrome/browser/ui/libgtkui/menu_util.h"
 
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/app/chrome_command_ids.h"
-#include "chrome/browser/ui/libgtk2ui/gtk2_util.h"
-#include "chrome/browser/ui/libgtk2ui/skia_utils_gtk2.h"
+#include "chrome/browser/ui/libgtkui/gtk2_util.h"
+#include "chrome/browser/ui/libgtkui/skia_utils_gtk2.h"
 #include "ui/base/accelerators/accelerator.h"
 #include "ui/base/accelerators/menu_label_accelerator_util_linux.h"
 #include "ui/base/models/menu_model.h"
 
 G_GNUC_BEGIN_IGNORE_DEPRECATIONS
 
-namespace libgtk2ui {
+namespace libgtkui {
 
 GtkWidget* BuildMenuItemWithImage(const std::string& label, GtkWidget* image) {
   GtkWidget* menu_item = gtk_image_menu_item_new_with_mnemonic(label.c_str());
   gtk_image_menu_item_set_image(GTK_IMAGE_MENU_ITEM(menu_item), image);
   return menu_item;
 }
 
 GtkWidget* BuildMenuItemWithImage(const std::string& label,
                                   const gfx::Image& icon) {
   GdkPixbuf* pixbuf = GdkPixbufFromSkBitmap(*icon.ToSkBitmap());
@@ skipping 226 matching lines @@
     }
 
     GtkWidget* submenu = gtk_menu_item_get_submenu(GTK_MENU_ITEM(widget));
     if (submenu) {
       gtk_container_foreach(
           GTK_CONTAINER(submenu), &SetMenuItemInfo, block_activation_ptr);
     }
   }
 }
 
-}  // namespace libgtk2ui
+}  // namespace libgtkui