Initial google_benchmark integration: source changes
diff --git a/.gitmodules b/.gitmodules
index 3665cde..c32881c 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -17,3 +17,6 @@
 [submodule "third_party/thrift"]
 	path = third_party/thrift
 	url = https://github.com/apache/thrift.git
+[submodule "third_party/google_benchmark"]
+	path = third_party/google_benchmark
+	url = https://github.com/google/benchmark