[libc][obvious] Remove the unused file utils/CPP/StringRef.h.

libc/utils/CPP/CMakeLists.txt

@@ -5,6 +5,5 @@ add_header_library(
     ArrayRef.h
     Bitset.h
     Functional.h
-    StringRef.h
     TypeTraits.h
 )

libc/utils/CPP/StringRef.h

@@ -1,24 +0,0 @@
-//===-- A standalone StringRef type -----------------------------*- C++ -*-===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef LLVM_LIBC_UTILS_CPP_STRINGREF_H
-#define LLVM_LIBC_UTILS_CPP_STRINGREF_H
-
-#include "ArrayRef.h"
-
-namespace __llvm_libc {
-namespace cpp {
-
-class StringRef : public ArrayRef<char> {
-  // More methods like those in llvm::StringRef can be added as needed.
-};
-
-} // namespace cpp
-} // namespace __llvm_libc
-
-#endif // LLVM_LIBC_UTILS_CPP_STRINGREF_H