Gtk3 ui: Add libgtk3ui as a separate build component

chrome/browser/ui/libgtkui/select_file_dialog_impl_gtk2.h

 // Copyright 2015 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_SELECT_FILE_DIALOG_IMPL_GTK2_H_
-#define CHROME_BROWSER_UI_LIBGTK2UI_SELECT_FILE_DIALOG_IMPL_GTK2_H_
+#ifndef CHROME_BROWSER_UI_LIBGTKUI_SELECT_FILE_DIALOG_IMPL_GTK2_H_
+#define CHROME_BROWSER_UI_LIBGTKUI_SELECT_FILE_DIALOG_IMPL_GTK2_H_
 
 #include "base/macros.h"
-#include "chrome/browser/ui/libgtk2ui/gtk2_signal.h"
-#include "chrome/browser/ui/libgtk2ui/gtk2_util.h"
-#include "chrome/browser/ui/libgtk2ui/select_file_dialog_impl.h"
+#include "chrome/browser/ui/libgtkui/gtk2_signal.h"
+#include "chrome/browser/ui/libgtkui/gtk2_util.h"
+#include "chrome/browser/ui/libgtkui/select_file_dialog_impl.h"
 
-namespace libgtk2ui {
+namespace libgtkui {
 
 // Implementation of SelectFileDialog that shows a Gtk common dialog for
 // choosing a file or folder. This acts as a modal dialog.
 class SelectFileDialogImplGTK : public SelectFileDialogImpl,
                                 public aura::WindowObserver {
  public:
   SelectFileDialogImplGTK(Listener* listener,
                           ui::SelectFilePolicy* policy);
 
  protected:
@@ skipping 95 matching lines @@
 
   // All our dialogs.
   std::set<GtkWidget*> dialogs_;
 
   // The set of all parent windows for which we are currently running dialogs.
   std::set<aura::Window*> parents_;
 
   DISALLOW_COPY_AND_ASSIGN(SelectFileDialogImplGTK);
 };
 
-}  // namespace libgtk2ui
+}  // namespace libgtkui
 
-#endif  // CHROME_BROWSER_UI_LIBGTK2UI_SELECT_FILE_DIALOG_IMPL_GTK2_H_
+#endif  // CHROME_BROWSER_UI_LIBGTKUI_SELECT_FILE_DIALOG_IMPL_GTK2_H_