This changes the base clipboard class.

base/clipboard.h

 // Copyright (c) 2006-2008 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"
 
-#if defined(OS_MACOSX)
-#if defined(__OBJC__)
-@class NSString;
-#else
-class NSString;
-#endif
-#endif
-
 class Clipboard {
  public:
-#if defined(OS_WIN)
-  typedef unsigned int FormatType;
-#elif defined(OS_MACOSX)
-  typedef NSString *FormatType;
-#elif defined(OS_LINUX)
-  typedef struct _GdkAtom* FormatType;
+  typedef std::string FormatType;
+#if defined(OS_LINUX)
   typedef struct _GtkClipboard GtkClipboard;
-  typedef std::map<std::string, std::pair<char*, size_t> > TargetMap;
+  typedef std::map<FormatType, std::pair<char*, size_t> > TargetMap;
 #endif
 
   // ObjectType designates the type of data to be stored in the clipboard. This
   // designation is shared across all OSes. The system-specific designation
   // is defined by FormatType. A single ObjectType might be represented by
   // several system-specific FormatTypes. For example, on Linux the CBF_TEXT
   // ObjectType maps to "text/plain", "STRING", and several other formats. On
   // windows it maps to CF_UNICODETEXT.
   enum ObjectType {
     CBF_TEXT,
@@ skipping 43 matching lines @@
   // kept until the system clipboard is set again.
   void WriteObjects(const ObjectMap& objects);
 
   // Behaves as above. If there is some shared memory handle passed as one of
   // the objects, it came from the process designated by |process|. This will
   // assist in turning it into a shared memory region that the current process
   // can use.
   void WriteObjects(const ObjectMap& objects, base::ProcessHandle process);
 
   // Tests whether the clipboard contains a certain format
-  bool IsFormatAvailable(FormatType format) const;
+  bool IsFormatAvailable(const FormatType& format) const;
 
   // Reads UNICODE text from the clipboard, if available.
   void ReadText(string16* result) const;
 
   // Reads ASCII text from the clipboard, if available.
   void ReadAsciiText(std::string* result) const;
 
   // Reads HTML from the clipboard, if available.
   void ReadHTML(string16* markup, std::string* src_url) const;
 
@@ skipping 57 matching lines @@
   void WriteBitmap(const char* pixel_data, const char* size_data);
 #if defined(OS_WIN)
   void WriteBitmapFromSharedMemory(const char* bitmap_data,
                                    const char* size_data,
                                    base::ProcessHandle handle);
 
   void WriteBitmapFromHandle(HBITMAP source_hbitmap,
                              const gfx::Size& size);
 
   // Safely write to system clipboard. Free |handle| on failure.
-  void WriteToClipboard(FormatType format, HANDLE handle);
+  void WriteToClipboard(unsigned int format, HANDLE handle);
 
   static void ParseBookmarkClipboardFormat(const string16& bookmark,
                                            string16* title,
                                            std::string* url);
 
   // Free a handle depending on its type (as intuited from format)
-  static void FreeData(FormatType format, HANDLE data);
+  static void FreeData(unsigned int format, HANDLE data);
 
   // Return the window that should be the clipboard owner, creating it
   // if neccessary.  Marked const for lazily initialization by const methods.
   HWND GetClipboardWindow() const;
 
   // Mark this as mutable so const methods can still do lazy initialization.
   mutable HWND clipboard_owner_;
 
   // True if we can create a window.
   bool create_window_;
@@ skipping 13 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_