Adding Google benchmarking library.

third_party/google_benchmark/test/cxx03_test.cc

+#undef NDEBUG
+#include <cassert>
+#include <cstddef>
+
+#include "benchmark/benchmark.h"
+
+#if __cplusplus >= 201103L
+#error C++11 or greater detected. Should be C++03.
+#endif
+
+void BM_empty(benchmark::State& state) {
+  while (state.KeepRunning()) {
+    volatile std::size_t x = state.iterations();
+    ((void)x);
+  }
+}
+BENCHMARK(BM_empty);
+
+// The new C++11 interface for args/ranges requires initializer list support.
+// Therefore we provide the old interface to support C++03.
+void BM_old_arg_range_interface(benchmark::State& state) {
+  assert((state.range(0) == 1 && state.range(1) == 2) ||
+         (state.range(0) == 5 && state.range(1) == 6));
+  while (state.KeepRunning()) {
+  }
+}
+BENCHMARK(BM_old_arg_range_interface)->ArgPair(1, 2)->RangePair(5, 5, 6, 6);
+
+template <class T, class U>
+void BM_template2(benchmark::State& state) {
+  BM_empty(state);
+}
+BENCHMARK_TEMPLATE2(BM_template2, int, long);
+
+template <class T>
+void BM_template1(benchmark::State& state) {
+  BM_empty(state);
+}
+BENCHMARK_TEMPLATE(BM_template1, long);
+BENCHMARK_TEMPLATE1(BM_template1, int);
+
+void BM_counters(benchmark::State& state) {
+    BM_empty(state);
+    state.counters["Foo"] = 2;
+}
+BENCHMARK(BM_counters);
+
+BENCHMARK_MAIN()