Gtk3 ui: Add libgtk3ui as a separate build component

chrome/browser/ui/libgtkui/gtk2_key_bindings_handler.h

 // Copyright (c) 2012 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.
 
-#ifndef CHROME_BROWSER_UI_LIBGTK2UI_GTK2_KEY_BINDINGS_HANDLER_H_
-#define CHROME_BROWSER_UI_LIBGTK2UI_GTK2_KEY_BINDINGS_HANDLER_H_
+#ifndef CHROME_BROWSER_UI_LIBGTKUI_GTK2_KEY_BINDINGS_HANDLER_H_
+#define CHROME_BROWSER_UI_LIBGTKUI_GTK2_KEY_BINDINGS_HANDLER_H_
 
 #include <gtk/gtk.h>
 
 #include <string>
 #include <vector>
 
 #include "base/event_types.h"
 #include "ui/base/ime/linux/text_edit_command_auralinux.h"
 
 namespace content {
 struct NativeWebKeyboardEvent;
 }
 
 namespace ui {
 class Event;
 }
 
-namespace libgtk2ui {
+namespace libgtkui {
 
 // This class is a convenience class for handling editor key bindings defined
 // in gtk keyboard theme.
 // In gtk, only GtkEntry and GtkTextView support customizing editor key bindings
 // through keyboard theme. And in gtk keyboard theme definition file, each key
 // binding must be bound to a specific class or object. So existing keyboard
 // themes only define editor key bindings exactly for GtkEntry and GtkTextView.
 // Then, the only way for us to intercept editor key bindings defined in
 // keyboard theme, is to create a GtkEntry or GtkTextView object and call
 // gtk_bindings_activate_event() against it for the key events. If a key event
@@ skipping 102 matching lines @@
   GtkWidget* fake_window_;
   GtkWidget* handler_;
 
   // Buffer to store the match results.
   std::vector<ui::TextEditCommandAuraLinux> edit_commands_;
 
   // Whether the current X server has the XKeyboard extension.
   bool has_xkb_;
 };
 
-}  // namespace libgtk2ui
+}  // namespace libgtkui
 
-#endif  // CHROME_BROWSER_UI_LIBGTK2UI_GTK2_KEY_BINDINGS_HANDLER_H_
+#endif  // CHROME_BROWSER_UI_LIBGTKUI_GTK2_KEY_BINDINGS_HANDLER_H_