Add NOTICE file

Also, update comment that refers to a LICENSE file that does not exist
to refer to the now-existing NOTICE file.

Change-Id: I7f628d9463b138fda53e3db6c20c354ca339a216
diff --git a/utf8_test.cpp b/utf8_test.cpp
index 472e82c..00113d7 100644
--- a/utf8_test.cpp
+++ b/utf8_test.cpp
@@ -58,7 +58,7 @@
 
 // Copyright (c) 2010 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.
+// found in the NOTICE file.
 
 // The tests below from utf_string_conversions_unittest.cc check for this
 // preprocessor symbol, so define it, as it is appropriate for Windows.