minidump: Use forward declarations in more places

minidump/minidump_writable.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_WRITABLE_H_
 #define CRASHPAD_MINIDUMP_MINIDUMP_WRITABLE_H_
 
 #include <dbghelp.h>
-#include <stdint.h>
 #include <sys/types.h>
 
-#include <limits>
 #include <vector>
 
 #include "base/basictypes.h"
-#include "util/file/file_writer.h"
 
 namespace crashpad {
+
+class FileWriterInterface;
+
 namespace internal {
 
 //! \brief The base class for all content that might be written to a minidump
 //!     file.
 class MinidumpWritable {
  public:
   //! \brief Writes an object and all of its children to a minidump file.
   //!
   //! Use this on the root object of a tree of MinidumpWritable objects,
   //! typically on a MinidumpFileWriter object.
@@ skipping 228 matching lines @@
   size_t leading_pad_bytes_;
   State state_;
 
   DISALLOW_COPY_AND_ASSIGN(MinidumpWritable);
 };
 
 }  // namespace internal
 }  // namespace crashpad
 
 #endif  // CRASHPAD_MINIDUMP_MINIDUMP_WRITABLE_H_