Add gmock into our dependencies.

third_party/boost/boost/type_traits/detail/wrap.hpp

Index: third_party/boost/boost/type_traits/detail/wrap.hpp
diff --git a/third_party/boost/boost/type_traits/detail/wrap.hpp b/third_party/boost/boost/type_traits/detail/wrap.hpp
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index 0000000000000000000000000000000000000000..d0a75d06cb70af480fdb5931f7335573cd3eee00
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+++ b/third_party/boost/boost/type_traits/detail/wrap.hpp
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+//  (C) Copyright David Abrahams 2002. 
+//  Use, modification and distribution are subject to the Boost Software License,
+//  Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+//  http://www.boost.org/LICENSE_1_0.txt).
+//
+//  See http://www.boost.org/libs/type_traits for most recent version including documentation.
+
+#ifndef BOOST_TT_DETAIL_WRAP_HPP_INCLUDED
+#define BOOST_TT_DETAIL_WRAP_HPP_INCLUDED
+
+namespace boost {
+namespace type_traits {
+
+template <class T> struct wrap {};
+
+}} // namespace boost::type_traits
+
+#endif // BOOST_TT_DETAIL_WRAP_HPP_INCLUDED