linux_aura: Port GtkKeybindingsHandler to Aura.

ui/wm/public/text_edit_key_bindings_delegate_x11.cc

+// Copyright 2014 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.
+
+#include "ui/wm/public/text_edit_key_bindings_delegate_x11.h"
+
+namespace ui {
+namespace wm {
+
+namespace {
+// Optional delegate. Unowned pointer.
+TextEditKeyBindingsDelegateX11* text_edit_keybinding_delegate_ = 0;
+}
+
+void SetTextEditKeyBindingsDelegate(TextEditKeyBindingsDelegateX11* delegate) {
+  text_edit_keybinding_delegate_ = delegate;
+}
+
+TextEditKeyBindingsDelegateX11* GetTextEditKeyBindingsDelegate() {
+  return text_edit_keybinding_delegate_;
+}
+
+}  // namespace wm
+}  // namespace ui