Add initial prototype for the GN meta-buildsystem.

tools/gn/standard_out.h

Index: tools/gn/standard_out.h
diff --git a/tools/gn/standard_out.h b/tools/gn/standard_out.h
new file mode 100644
index 0000000000000000000000000000000000000000..2eb525bd46976cfa1a40dd87c16a465650c38327
--- /dev/null
+++ b/tools/gn/standard_out.h
@@ -0,0 +1,22 @@
+// Copyright (c) 2013 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.
+
+#ifndef TOOLS_GN_STANDARD_OUT_H_
+#define TOOLS_GN_STANDARD_OUT_H_
+
+#include <string>
+
+enum TextDecoration {
+  DECORATION_NONE = 0,
+  DECORATION_BOLD,
+  DECORATION_RED,
+  DECORATION_GREEN,
+  DECORATION_BLUE,
+  DECORATION_YELLOW
+};
+
+void OutputString(const std::string& output,
+                  TextDecoration dec = DECORATION_NONE);
+
+#endif  // TOOLS_GN_STANDARD_OUT_H_