minidump: Use forward declarations in more places

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,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
 #ifndef CRASHPAD_MINIDUMP_MINIDUMP_STRING_WRITER_H_
 #define CRASHPAD_MINIDUMP_MINIDUMP_STRING_WRITER_H_
 
 #include <dbghelp.h>
-#include <stdint.h>
-#include <sys/types.h>
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/strings/string16.h"
 #include "minidump/minidump_extensions.h"
 #include "minidump/minidump_writable.h"
-#include "util/file/file_writer.h"
 
 namespace crashpad {
 namespace internal {
 
 //! \cond
 
 struct MinidumpStringWriterUTF16Traits {
   typedef string16 StringType;
   typedef MINIDUMP_STRING MinidumpStringType;
 };
@@ skipping 85 matching lines @@
   const std::string& UTF8() const { return string(); }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MinidumpUTF8StringWriter);
 };
 
 }  // namespace internal
 }  // namespace crashpad
 
 #endif  // CRASHPAD_MINIDUMP_MINIDUMP_STRING_WRITER_H_