Add MinidumpSimpleStringDictionaryWriter and its test

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 51 matching lines @@
 
   bool Freeze() override;
   size_t SizeOfObject() override;
   bool WriteObject(FileWriterInterface* file_writer) override;
 
   //! \brief Sets the string to be written.
   //!
   //! \note Valid in #kStateMutable.
   void set_string(const StringType& string) { string_.assign(string); }
 
+  //! \brief Retrieves the string to be written.
+  //!
+  //! \note Valid in any state.
+  const StringType& string() const { return string_; }
+
  private:
   MinidumpStringType string_base_;
   StringType string_;
 
   DISALLOW_COPY_AND_ASSIGN(MinidumpStringWriter);
 };
 
 //! \brief Writes a variable-length UTF-16-encoded MINIDUMP_STRING to a minidump
 //!     file.
 //!
@@ skipping 24 matching lines @@
     : public MinidumpStringWriter<MinidumpStringWriterUTF8Traits> {
  public:
   MinidumpUTF8StringWriter() : MinidumpStringWriter() {}
   ~MinidumpUTF8StringWriter() {}
 
   //! \brief Sets the string to be written.
   //!
   //! \note Valid in #kStateMutable.
   void SetUTF8(const std::string& string_utf8) { set_string(string_utf8); }
 
+  //! \brief Retrieves the string to be written.
+  //!
+  //! \note Valid in any state.
+  const std::string& UTF8() const { return string(); }
+
  private:
   DISALLOW_COPY_AND_ASSIGN(MinidumpUTF8StringWriter);
 };
 
 }  // namespace internal
 }  // namespace crashpad
 
 #endif  // CRASHPAD_MINIDUMP_MINIDUMP_STRING_WRITER_H_