Now that we deal with string16s, provide some useful conversions for them.

base/sys_string_conversions.h

Index: base/sys_string_conversions.h
===================================================================
--- base/sys_string_conversions.h	(revision 9943)
+++ base/sys_string_conversions.h	(working copy)
@@ -11,6 +11,7 @@
 
 #include <string>
 #include "base/basictypes.h"
+#include "base/string16.h"
 
 #if defined(OS_MACOSX)
 #include <CoreFoundation/CoreFoundation.h>
@@ -57,18 +58,22 @@
 // Creates a string, and returns it with a refcount of 1. You are responsible
 // for releasing it. Returns NULL on failure.
 CFStringRef SysUTF8ToCFStringRef(const std::string& utf8);
+CFStringRef SysUTF16ToCFStringRef(const string16& utf16);
 CFStringRef SysWideToCFStringRef(const std::wstring& wide);
 
 // Same, but returns an autoreleased NSString.
 NSString* SysUTF8ToNSString(const std::string& utf8);
+NSString* SysUTF16ToNSString(const string16& utf16);
 NSString* SysWideToNSString(const std::wstring& wide);
 
 // Converts a CFStringRef to an STL string. Returns an empty string on failure.
 std::string SysCFStringRefToUTF8(CFStringRef ref);
+string16 SysCFStringRefToUTF16(CFStringRef ref);
 std::wstring SysCFStringRefToWide(CFStringRef ref);
 
 // Same, but accepts NSString input.
 std::string SysNSStringToUTF8(NSString* ref);
+string16 SysNSStringToUTF16(NSString* ref);
 std::wstring SysNSStringToWide(NSString* ref);
 
 #endif  // defined(OS_MACOSX)