Add XStream to Chromium third_party.

third_party/xstream/LICENSE

Index: third_party/xstream/LICENSE
diff --git a/third_party/xstream/LICENSE b/third_party/xstream/LICENSE
new file mode 100644
index 0000000000000000000000000000000000000000..8fee1a0001cf299762316e83ddeb0aca9716f4b3
--- /dev/null
+++ b/third_party/xstream/LICENSE
@@ -0,0 +1,28 @@
+Copyright (c) 2003-2006, Joe Walnes
+Copyright (c) 2006-2015 XStream Committers
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this list of
+conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice, this list of
+conditions and the following disclaimer in the documentation and/or other materials provided
+with the distribution.
+
+3. Neither the name of XStream nor the names of its contributors may be used to endorse
+or promote products derived from this software without specific prior written
+permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
+WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+DAMAGE.