Make File-Picker modal on Linux

chrome/browser/ui/libgtk2ui/select_file_dialog_impl_kde.cc

Index: chrome/browser/ui/libgtk2ui/select_file_dialog_impl_kde.cc
diff --git a/chrome/browser/ui/libgtk2ui/select_file_dialog_impl_kde.cc b/chrome/browser/ui/libgtk2ui/select_file_dialog_impl_kde.cc
index b7016dce0a278e444098859b064820fc7bfd2cca..30d1573cbbf4613f3c1b194facf7adee911c5236 100644
--- a/chrome/browser/ui/libgtk2ui/select_file_dialog_impl_kde.cc
+++ b/chrome/browser/ui/libgtk2ui/select_file_dialog_impl_kde.cc
@@ -50,6 +50,7 @@ class SelectFileDialogImplKDE : public SelectFileDialogImpl {
   SelectFileDialogImplKDE(Listener* listener,
                           ui::SelectFilePolicy* policy,
                           base::nix::DesktopEnvironment desktop);
+  void CloseImpl() override;
 
  protected:
   ~SelectFileDialogImplKDE() override;
@@ -198,6 +199,9 @@ SelectFileDialogImplKDE::SelectFileDialogImplKDE(
          desktop_ == base::nix::DESKTOP_ENVIRONMENT_KDE4);
 }
 
+void SelectFileDialogImplKDE::CloseImpl() {
+}
+
 SelectFileDialogImplKDE::~SelectFileDialogImplKDE() {
 }