split ui/base/clipboard constants out for split_link

ui/base/clipboard/clipboard_constants.cc

+// Copyright 2013 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/base/clipboard/clipboard.h"
+
+namespace ui {
+
+const char Clipboard::kMimeTypeText[] = "text/plain";
+const char Clipboard::kMimeTypeURIList[] = "text/uri-list";
+const char Clipboard::kMimeTypeDownloadURL[] = "downloadurl";
+const char Clipboard::kMimeTypeHTML[] = "text/html";
+const char Clipboard::kMimeTypeRTF[] = "text/rtf";
+const char Clipboard::kMimeTypePNG[] = "image/png";
+
+}  // namespace ui