Gtk3 ui: Add libgtk3ui as a separate build component

chrome/browser/ui/libgtkui/app_indicator_icon_menu.h

Index: chrome/browser/ui/libgtkui/app_indicator_icon_menu.h
diff --git a/chrome/browser/ui/libgtk2ui/app_indicator_icon_menu.h b/chrome/browser/ui/libgtkui/app_indicator_icon_menu.h
similarity index 86%
rename from chrome/browser/ui/libgtk2ui/app_indicator_icon_menu.h
rename to chrome/browser/ui/libgtkui/app_indicator_icon_menu.h
index 40f02adeb3c156687b7f9c060d056dbc1ebd023b..1c38658d732b915180c5f51abdce3a877f11cbdb 100644
--- a/chrome/browser/ui/libgtk2ui/app_indicator_icon_menu.h
+++ b/chrome/browser/ui/libgtkui/app_indicator_icon_menu.h
@@ -2,12 +2,12 @@
 // 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_APP_INDICATOR_ICON_MENU_H_
-#define CHROME_BROWSER_UI_LIBGTK2UI_APP_INDICATOR_ICON_MENU_H_
+#ifndef CHROME_BROWSER_UI_LIBGTKUI_APP_INDICATOR_ICON_MENU_H_
+#define CHROME_BROWSER_UI_LIBGTKUI_APP_INDICATOR_ICON_MENU_H_
 
 #include "base/callback.h"
 #include "base/macros.h"
-#include "chrome/browser/ui/libgtk2ui/gtk2_signal.h"
+#include "chrome/browser/ui/libgtkui/gtk2_signal.h"
 
 typedef struct _GtkMenu GtkMenu;
 typedef struct _GtkWidget GtkWidget;
@@ -16,7 +16,7 @@ namespace ui {
 class MenuModel;
 }
 
-namespace libgtk2ui {
+namespace libgtkui {
 
 // The app indicator icon's menu.
 class AppIndicatorIconMenu {
@@ -62,6 +62,6 @@ class AppIndicatorIconMenu {
   DISALLOW_COPY_AND_ASSIGN(AppIndicatorIconMenu);
 };
 
-}  // namespace libgtk2ui
+}  // namespace libgtkui
 
-#endif  // CHROME_BROWSER_UI_LIBGTK2UI_APP_INDICATOR_ICON_MENU_H_
+#endif  // CHROME_BROWSER_UI_LIBGTKUI_APP_INDICATOR_ICON_MENU_H_