Clean up rewrite_to_chrome_style naming logic.

tools/clang/rewrite_to_chrome_style/Renamer.h

Index: tools/clang/rewrite_to_chrome_style/Renamer.h
diff --git a/tools/clang/rewrite_to_chrome_style/Renamer.h b/tools/clang/rewrite_to_chrome_style/Renamer.h
new file mode 100644
index 0000000000000000000000000000000000000000..792b0101d4b4c1dab74863254966b0177d75315e
--- /dev/null
+++ b/tools/clang/rewrite_to_chrome_style/Renamer.h
@@ -0,0 +1,11 @@
+// Copyright 2016 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 <string>
+
+#include "llvm/ADT/StringRef.h"
+
+std::string IdentifierToCamelCase(llvm::StringRef input);
+std::string IdentifierToUnderscoreCase(llvm::StringRef input);
+std::string identifierToShoutyCase(llvm::StringRef input);