Pull the new r369476 of base library from Chromium

The merge was done against r369476 which corresponds to git commit
0471d0e2e2ef4a544a63481a389e1df33ea7c00a of Jan 14, 2016

Change-Id: Ie6894cf65424cc5ad115110faccd51602b2d1234
Reviewed-on: https://weave-review.googlesource.com/2225
Reviewed-by: Alex Vakulenko <avakulenko@google.com>
diff --git a/third_party/chromium/base/strings/string_piece_unittest.cc b/third_party/chromium/base/strings/string_piece_unittest.cc
index 2c2b0a6..5772acd 100644
--- a/third_party/chromium/base/strings/string_piece_unittest.cc
+++ b/third_party/chromium/base/strings/string_piece_unittest.cc
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include <stddef.h>
+
 #include <string>
 
 #include <gtest/gtest.h>