Fix mac after https://codereview.chromium.org/1419623003/

minidump/minidump_string_writer.h

 // Copyright 2014 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 81 matching lines @@
  public:
   MinidumpUTF16StringWriter() : MinidumpStringWriter() {}
   ~MinidumpUTF16StringWriter() override;
 
   //! \brief Converts a UTF-8 string to UTF-16 and sets it as the string to be
   //!     written.
   //!
   //! \note Valid in #kStateMutable.
   void SetUTF8(const std::string& string_utf8);
 
-  //! \brief Sets the given UTF-16 string as the string to be written.
-  //!
-  //! \note Valid in #kStateMutable.
-  void SetUTF16(const base::string16& string_utf16) {
-    set_string(string_utf16);
-  }
-
  private:
   DISALLOW_COPY_AND_ASSIGN(MinidumpUTF16StringWriter);
 };
 
 //! \brief Writes a variable-length UTF-8-encoded MinidumpUTF8String to a
 //!     minidump file.
 //!
 //! MinidumpUTF8StringWriter objects should not be instantiated directly outside
 //! of the MinidumpWritable family of classes.
 class MinidumpUTF8StringWriter final
@@ skipping 62 matching lines @@
 }  // namespace internal
 
 using MinidumpUTF16StringListWriter = internal::MinidumpStringListWriter<
     internal::MinidumpUTF16StringWriter>;
 using MinidumpUTF8StringListWriter = internal::MinidumpStringListWriter<
     internal::MinidumpUTF8StringWriter>;
 
 }  // namespace crashpad
 
 #endif  // CRASHPAD_MINIDUMP_MINIDUMP_STRING_WRITER_H_