Adding Google benchmarking library.

third_party/google_benchmark/src/colorprint.h

Index: third_party/google_benchmark/src/colorprint.h
diff --git a/third_party/google_benchmark/src/colorprint.h b/third_party/google_benchmark/src/colorprint.h
new file mode 100644
index 0000000000000000000000000000000000000000..9f6fab9b342268dc7d246aa9e5d265c136e7853a
--- /dev/null
+++ b/third_party/google_benchmark/src/colorprint.h
@@ -0,0 +1,33 @@
+#ifndef BENCHMARK_COLORPRINT_H_
+#define BENCHMARK_COLORPRINT_H_
+
+#include <cstdarg>
+#include <iostream>
+#include <string>
+
+namespace benchmark {
+enum LogColor {
+  COLOR_DEFAULT,
+  COLOR_RED,
+  COLOR_GREEN,
+  COLOR_YELLOW,
+  COLOR_BLUE,
+  COLOR_MAGENTA,
+  COLOR_CYAN,
+  COLOR_WHITE
+};
+
+std::string FormatString(const char* msg, va_list args);
+std::string FormatString(const char* msg, ...);
+
+void ColorPrintf(std::ostream& out, LogColor color, const char* fmt,
+                 va_list args);
+void ColorPrintf(std::ostream& out, LogColor color, const char* fmt, ...);
+
+// Returns true if stdout appears to be a terminal that supports colored
+// output, false otherwise.
+bool IsColorTerminal();
+
+}  // end namespace benchmark
+
+#endif  // BENCHMARK_COLORPRINT_H_