Gtk3 ui: Add libgtk3ui as a separate build component

chrome/browser/ui/libgtkui/select_file_dialog_impl_kde.cc

Index: chrome/browser/ui/libgtkui/select_file_dialog_impl_kde.cc
diff --git a/chrome/browser/ui/libgtk2ui/select_file_dialog_impl_kde.cc b/chrome/browser/ui/libgtkui/select_file_dialog_impl_kde.cc
similarity index 99%
rename from chrome/browser/ui/libgtk2ui/select_file_dialog_impl_kde.cc
rename to chrome/browser/ui/libgtkui/select_file_dialog_impl_kde.cc
index 7b9882987edd31819756385a272ab66bbc7ddd0a..182d28910686d8f5d3659209040b7aee47305715 100644
--- a/chrome/browser/ui/libgtk2ui/select_file_dialog_impl_kde.cc
+++ b/chrome/browser/ui/libgtkui/select_file_dialog_impl_kde.cc
@@ -21,7 +21,7 @@
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/thread_restrictions.h"
-#include "chrome/browser/ui/libgtk2ui/select_file_dialog_impl.h"
+#include "chrome/browser/ui/libgtkui/select_file_dialog_impl.h"
 #include "chrome/grit/generated_resources.h"
 #include "content/public/browser/browser_thread.h"
 #include "ui/aura/window_tree_host.h"
@@ -44,7 +44,7 @@ const char kKdialogBinary[] = "kdialog";
 
 }  // namespace
 
-namespace libgtk2ui {
+namespace libgtkui {
 
 // Implementation of SelectFileDialog that shows a KDE common dialog for
 // choosing a file or folder. This acts as a modal dialog.
@@ -524,4 +524,4 @@ void SelectFileDialogImplKDE::OnSelectMultiFileDialogResponse(
   MultiFilesSelected(filenames_fp, params);
 }
 
-}  // namespace libgtk2ui
+}  // namespace libgtkui