Audit all of sky's system <> style includes

sky/engine/wtf/text/WTFString.h

 /*
  * (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2013 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 14 matching lines @@
 // This file would be called String.h, but that conflicts with <string.h>
 // on systems without case-sensitive file systems.
 #include <string>
 
 #include "wtf/HashTableDeletedValueType.h"
 #include "wtf/WTFExport.h"
 #include "wtf/text/ASCIIFastPath.h"
 #include "wtf/text/StringImpl.h"
 #include "wtf/text/StringView.h"
 
-#ifdef __OBJC__
-#include <objc/objc.h>
-#endif
-
 namespace WTF {
 
 class CString;
 struct StringHash;
 
 // Declarations of string operations
 
 WTF_EXPORT int charactersToIntStrict(const LChar*, size_t, bool* ok = 0, int base = 10);
 WTF_EXPORT int charactersToIntStrict(const UChar*, size_t, bool* ok = 0, int base = 10);
 WTF_EXPORT unsigned charactersToUIntStrict(const LChar*, size_t, bool* ok = 0, int base = 10);
@@ skipping 635 matching lines @@
 using WTF::charactersToFloat;
 using WTF::equal;
 using WTF::equalIgnoringCase;
 using WTF::find;
 using WTF::isAllSpecialCharacters;
 using WTF::isSpaceOrNewline;
 using WTF::reverseFind;
 
 #include "wtf/text/AtomicString.h"
 #endif // WTFString_h