Add gmock into our dependencies.

third_party/boost/boost/fusion/adapted/struct/detail/at_key_impl.hpp

Index: third_party/boost/boost/fusion/adapted/struct/detail/at_key_impl.hpp
diff --git a/third_party/boost/boost/fusion/adapted/struct/detail/at_key_impl.hpp b/third_party/boost/boost/fusion/adapted/struct/detail/at_key_impl.hpp
new file mode 100644
index 0000000000000000000000000000000000000000..4ce0fce9e462e7594737559fa80d9cb05cdd51dc
--- /dev/null
+++ b/third_party/boost/boost/fusion/adapted/struct/detail/at_key_impl.hpp
@@ -0,0 +1,54 @@
+/*=============================================================================
+    Copyright (c) 2001-2007 Joel de Guzman
+    Copyright (c) 2005-2007 Dan Marsden
+
+    Distributed under 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)
+==============================================================================*/
+#if !defined(BOOST_FUSION_AT_KEY_IMPL_20070508_2248)
+#define BOOST_FUSION_AT_KEY_IMPL_20070508_2248
+
+#include <boost/fusion/support/detail/access.hpp>
+
+namespace boost { namespace fusion
+{
+    struct struct_tag;
+
+    namespace extension
+    {
+        template<typename T>
+        struct at_key_impl;
+
+        template <typename Struct, typename Key>
+        struct struct_assoc_member;
+
+        template <>
+        struct at_key_impl<struct_tag>
+        {
+            template <typename Sequence, typename Key>
+            struct apply
+            {
+                typedef typename
+                extension::struct_assoc_member<Sequence, Key>
+                element;
+
+                typedef typename
+                    mpl::eval_if<
+                        is_const<Sequence>
+                      , detail::cref_result<element>
+                      , detail::ref_result<element>
+                    >::type
+                type;
+
+                static type
+                call(Sequence& seq)
+                {
+                    return extension::
+                        struct_assoc_member<Sequence, Key>::call(seq);
+                }
+            };
+        };
+    }
+}}
+
+#endif