Reduce header dependencies in base/

base/clipboard.h

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_CLIPBOARD_H_
 #define BASE_CLIPBOARD_H_
 
 #include <map>
 #include <string>
 #include <vector>
 
-#include "base/file_path.h"
 #include "base/process.h"
 #include "base/string16.h"
-#include "base/gfx/size.h"
+
+namespace gfx {
+class Size;
+}
+
+class FilePath;
 
 class Clipboard {
  public:
   typedef std::string FormatType;
 #if defined(OS_LINUX)
   typedef struct _GtkClipboard GtkClipboard;
   typedef std::map<FormatType, std::pair<char*, size_t> > TargetMap;
 #endif
 
   // ObjectType designates the type of data to be stored in the clipboard. This
@@ skipping 169 matching lines @@
   void InsertMapping(const char* key, char* data, size_t data_len);
 
   TargetMap* clipboard_data_;
   GtkClipboard* clipboard_;
 #endif
 
   DISALLOW_EVIL_CONSTRUCTORS(Clipboard);
 };
 
 #endif  // BASE_CLIPBOARD_H_