Revert of Remove webrtc/libjingle/{xmllite,xmpp}

webrtc/libjingle/xmllite/xmlconstants.cc

+/*
+ *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/libjingle/xmllite/xmlconstants.h"
+
+namespace buzz {
+
+const char STR_EMPTY[] = "";
+const char NS_XML[] = "http://www.w3.org/XML/1998/namespace";
+const char NS_XMLNS[] = "http://www.w3.org/2000/xmlns/";
+const char STR_XMLNS[] = "xmlns";
+const char STR_XML[] = "xml";
+const char STR_VERSION[] = "version";
+const char STR_ENCODING[] = "encoding";
+
+const StaticQName QN_XMLNS = { STR_EMPTY, STR_XMLNS };
+
+}  // namespace buzz