Implement ui::ClipboardMus.

ui/base/clipboard/custom_data_helper_linux.cc

Index: ui/base/clipboard/custom_data_helper_linux.cc
diff --git a/ui/base/clipboard/custom_data_helper_linux.cc b/ui/base/clipboard/custom_data_helper_linux.cc
deleted file mode 100644
index d8cc89edff558d052a49bd61121b7e58301aa0aa..0000000000000000000000000000000000000000
--- a/ui/base/clipboard/custom_data_helper_linux.cc
+++ /dev/null
@@ -1,13 +0,0 @@
-// Copyright (c) 2011 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 "build/build_config.h"
-#include "ui/base/clipboard/custom_data_helper.h"
-
-namespace ui {
-
-// TODO(dcheng): This name is temporary. See crbug.com/106449
-const char kMimeTypeWebCustomData[] = "chromium/x-web-custom-data";
-
-}  // namespace ui