This changes the base clipboard class.

base/clipboard_mac.mm

 // 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.
 
 #include "base/clipboard.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/logging.h"
 #include "base/string_util.h"
@@ skipping 111 matching lines @@
 
   NSPasteboard* pb = GetPasteboard();
   [pb addTypes:[NSArray arrayWithObject:NSFilenamesPboardType] owner:nil];
   [pb setPropertyList:fileList forType:NSFilenamesPboardType];
 }
 
 // Write an extra flavor that signifies WebKit was the last to modify the
 // pasteboard. This flavor has no data.
 void Clipboard::WriteWebSmartPaste() {
   NSPasteboard* pb = GetPasteboard();
-  [pb addTypes:[NSArray arrayWithObject:GetWebKitSmartPasteFormatType()] owner:nil];
-  [pb setData:nil forType:GetWebKitSmartPasteFormatType()];
+  NSString* format = base::SysUTF8ToNSString(GetWebKitSmartPasteFormatType());
+  [pb addTypes:[NSArray arrayWithObject:format] owner:nil];
+  [pb setData:nil forType:format];
 }
 
-bool Clipboard::IsFormatAvailable(NSString* format) const {
+bool Clipboard::IsFormatAvailable(const Clipboard::FormatType& format) const {
+  NSString* format_ns = base::SysUTF8ToNSString(format);
+
   NSPasteboard* pb = GetPasteboard();
   NSArray* types = [pb types];
 
-  return [types containsObject:format];
+  return [types containsObject:format_ns];
 }
 
 void Clipboard::ReadText(string16* result) const {
   NSPasteboard* pb = GetPasteboard();
   NSString* contents = [pb stringForType:NSStringPboardType];
 
   UTF8ToUTF16([contents UTF8String],
               [contents lengthOfBytesUsingEncoding:NSUTF8StringEncoding],
               result);
 }
@@ skipping 72 matching lines @@
   NSArray* fileList = [pb propertyListForType:NSFilenamesPboardType];
 
   for (unsigned int i = 0; i < [fileList count]; ++i) {
     std::string file = [[fileList objectAtIndex:i] UTF8String];
     files->push_back(FilePath(file));
   }
 }
 
 // static
 Clipboard::FormatType Clipboard::GetUrlFormatType() {
-  return NSURLPboardType;
+  static const std::string type = base::SysNSStringToUTF8(NSURLPboardType);
+  return type;
 }
 
 // static
 Clipboard::FormatType Clipboard::GetUrlWFormatType() {
-  return NSURLPboardType;
+  static const std::string type = base::SysNSStringToUTF8(NSURLPboardType);
+  return type;
 }
 
 // static
 Clipboard::FormatType Clipboard::GetPlainTextFormatType() {
-  return NSStringPboardType;
+  static const std::string type = base::SysNSStringToUTF8(NSStringPboardType);
+  return type;
 }
 
 // static
 Clipboard::FormatType Clipboard::GetPlainTextWFormatType() {
-  return NSStringPboardType;
+  static const std::string type = base::SysNSStringToUTF8(NSStringPboardType);
+  return type;
 }
 
 // static
 Clipboard::FormatType Clipboard::GetFilenameFormatType() {
-  return NSFilenamesPboardType;
+  static const std::string type =
+      base::SysNSStringToUTF8(NSFilenamesPboardType);
+  return type;
 }
 
 // static
 Clipboard::FormatType Clipboard::GetFilenameWFormatType() {
-  return NSFilenamesPboardType;
+  static const std::string type =
+      base::SysNSStringToUTF8(NSFilenamesPboardType);
+  return type;
 }
 
 // static
 Clipboard::FormatType Clipboard::GetHtmlFormatType() {
-  return NSHTMLPboardType;
+  static const std::string type = base::SysNSStringToUTF8(NSHTMLPboardType);
+  return type;
 }
 
 // static
 Clipboard::FormatType Clipboard::GetWebKitSmartPasteFormatType() {
-  return kWebSmartPastePboardType;
+  static const std::string type =
+      base::SysNSStringToUTF8(kWebSmartPastePboardType);
+  return type;
 }