Gtk3 ui: Add libgtk3ui as a separate build component

chrome/browser/ui/libgtkui/menu_util.h

Index: chrome/browser/ui/libgtkui/menu_util.h
diff --git a/chrome/browser/ui/libgtk2ui/menu_util.h b/chrome/browser/ui/libgtkui/menu_util.h
similarity index 90%
rename from chrome/browser/ui/libgtk2ui/menu_util.h
rename to chrome/browser/ui/libgtkui/menu_util.h
index c81d32dcb915c15d19d51a94eecd09c64f144c7a..9741e81380c556d0177689cf4ed04106ab26248d 100644
--- a/chrome/browser/ui/libgtk2ui/menu_util.h
+++ b/chrome/browser/ui/libgtkui/menu_util.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CHROME_BROWSER_UI_LIBGTK2UI_MENU_UTIL_H_
-#define CHROME_BROWSER_UI_LIBGTK2UI_MENU_UTIL_H_
+#ifndef CHROME_BROWSER_UI_LIBGTKUI_MENU_UTIL_H_
+#define CHROME_BROWSER_UI_LIBGTKUI_MENU_UTIL_H_
 
 #include <gtk/gtk.h>
 
@@ -13,7 +13,7 @@ namespace ui {
 class MenuModel;
 }
 
-namespace libgtk2ui {
+namespace libgtkui {
 // Builds GtkImageMenuItems.
 GtkWidget* BuildMenuItemWithImage(const std::string& label, GtkWidget* image);
 GtkWidget* BuildMenuItemWithImage(const std::string& label,
@@ -51,6 +51,6 @@ void BuildSubmenuFromModel(ui::MenuModel* model,
 // Sets the check mark, enabled/disabled state and dynamic labels on menu items.
 void SetMenuItemInfo(GtkWidget* widget, void* block_activation_ptr);
 
-}  // namespace libgtk2ui
+}  // namespace libgtkui
 
-#endif  // CHROME_BROWSER_UI_LIBGTK2UI_MENU_UTIL_H_
+#endif  // CHROME_BROWSER_UI_LIBGTKUI_MENU_UTIL_H_