Adding Google benchmarking library.

base/test/run_all_base_microbenchmarks.cc

Index: base/test/run_all_base_microbenchmarks.cc
diff --git a/base/test/run_all_base_microbenchmarks.cc b/base/test/run_all_base_microbenchmarks.cc
new file mode 100644
index 0000000000000000000000000000000000000000..442c68f4f1258e3770d846c03e9b7154cdc9182a
--- /dev/null
+++ b/base/test/run_all_base_microbenchmarks.cc
@@ -0,0 +1,7 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "third_party/google_benchmark/include/benchmark/benchmark.h"
+
+BENCHMARK_MAIN();