Gtk3 ui: Add libgtk3ui as a separate build component

chrome/browser/ui/libgtkui/gtk2_signal.h

Index: chrome/browser/ui/libgtkui/gtk2_signal.h
diff --git a/chrome/browser/ui/libgtk2ui/gtk2_signal.h b/chrome/browser/ui/libgtkui/gtk2_signal.h
similarity index 95%
rename from chrome/browser/ui/libgtk2ui/gtk2_signal.h
rename to chrome/browser/ui/libgtkui/gtk2_signal.h
index 4643b98dc45bc62cdb723e4647b82075d3ec26d6..19d98e89b8c2ad700bd8d7f1561994e6e84b6ab6 100644
--- a/chrome/browser/ui/libgtk2ui/gtk2_signal.h
+++ b/chrome/browser/ui/libgtkui/gtk2_signal.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_GTK2_SIGNAL_H_
-#define CHROME_BROWSER_UI_LIBGTK2UI_GTK2_SIGNAL_H_
+#ifndef CHROME_BROWSER_UI_LIBGTKUI_GTK2_SIGNAL_H_
+#define CHROME_BROWSER_UI_LIBGTKUI_GTK2_SIGNAL_H_
 
 #include "ui/base/glib/glib_signal.h"
 
@@ -65,4 +65,4 @@ typedef struct _GtkWidget GtkWidget;
   CHROMEG_VIRTUAL_CALLBACK_6(CLASS, RETURN, METHOD, GtkWidget*, ARG1, ARG2,   \
                              ARG3, ARG4, ARG5, ARG6);
 
-#endif  // CHROME_BROWSER_UI_LIBGTK2UI_GTK2_SIGNAL_H_
+#endif  // CHROME_BROWSER_UI_LIBGTKUI_GTK2_SIGNAL_H_