Gtk3 ui: Add libgtk3ui as a separate build component

chrome/browser/ui/libgtkui/app_indicator_icon_menu.cc

Index: chrome/browser/ui/libgtkui/app_indicator_icon_menu.cc
diff --git a/chrome/browser/ui/libgtk2ui/app_indicator_icon_menu.cc b/chrome/browser/ui/libgtkui/app_indicator_icon_menu.cc
similarity index 95%
rename from chrome/browser/ui/libgtk2ui/app_indicator_icon_menu.cc
rename to chrome/browser/ui/libgtkui/app_indicator_icon_menu.cc
index 151117314c8359424cae60c6e4c1dd2814f89f08..91674b98f9210297f650a8c5ce962ba38cf658d4 100644
--- a/chrome/browser/ui/libgtk2ui/app_indicator_icon_menu.cc
+++ b/chrome/browser/ui/libgtkui/app_indicator_icon_menu.cc
@@ -2,16 +2,16 @@
 // 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/app_indicator_icon_menu.h"
+#include "chrome/browser/ui/libgtkui/app_indicator_icon_menu.h"
 
 #include <gtk/gtk.h>
 
 #include "base/bind.h"
 #include "base/debug/leak_annotations.h"
-#include "chrome/browser/ui/libgtk2ui/menu_util.h"
+#include "chrome/browser/ui/libgtkui/menu_util.h"
 #include "ui/base/models/menu_model.h"
 
-namespace libgtk2ui {
+namespace libgtkui {
 
 AppIndicatorIconMenu::AppIndicatorIconMenu(ui::MenuModel* model)
     : menu_model_(model),
@@ -120,4 +120,4 @@ void AppIndicatorIconMenu::OnMenuItemActivated(GtkWidget* menu_item) {
     ExecuteCommand(model, id);
 }
 
-}  // namespace libgtk2ui
+}  // namespace libgtkui