Add gmock into our dependencies.

third_party/boost/boost/fusion/support/is_iterator.hpp

Index: third_party/boost/boost/fusion/support/is_iterator.hpp
diff --git a/third_party/boost/boost/fusion/support/is_iterator.hpp b/third_party/boost/boost/fusion/support/is_iterator.hpp
new file mode 100644
index 0000000000000000000000000000000000000000..9e775f4e52a42769cdd18b11fc970391028c6c21
--- /dev/null
+++ b/third_party/boost/boost/fusion/support/is_iterator.hpp
@@ -0,0 +1,20 @@
+/*=============================================================================
+    Copyright (c) 2001-2006 Joel de Guzman
+
+    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(FUSION_IS_ITERATOR_05062005_1219)
+#define FUSION_IS_ITERATOR_05062005_1219
+
+#include <boost/type_traits/is_base_of.hpp>
+
+namespace boost { namespace fusion
+{
+    struct iterator_root;
+
+    template <typename T>
+    struct is_fusion_iterator : is_base_of<iterator_root, T> {};
+}}
+
+#endif