Define a variable to distinguish system_icu from bundled_icu in Blink

Source/wtf/text/TextCodecICU.h

 /*
  * Copyright (C) 2004, 2006, 2007, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov <ap@nypop.com>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 40 matching lines @@
     virtual String decode(const char*, size_t length, FlushBehavior, bool stopOnError, bool& sawError) override;
     virtual CString encode(const UChar*, size_t length, UnencodableHandling) override;
     virtual CString encode(const LChar*, size_t length, UnencodableHandling) override;
 
     template<typename CharType>
     CString encodeCommon(const CharType*, size_t length, UnencodableHandling);
     CString encodeInternal(const TextCodecInput&, UnencodableHandling);
 
     void createICUConverter() const;
     void releaseICUConverter() const;
+#if defined(USING_SYSTEM_ICU)
     bool needsGBKFallbacks() const { return m_needsGBKFallbacks; }
     void setNeedsGBKFallbacks(bool needsFallbacks) { m_needsGBKFallbacks = needsFallbacks; }
+#endif
 
     int decodeToBuffer(UChar* buffer, UChar* bufferLimit, const char*& source,
         const char* sourceLimit, int32_t* offsets, bool flush, UErrorCode&);
 
     TextEncoding m_encoding;
     mutable UConverter* m_converterICU;
+#if defined(USING_SYSTEM_ICU)
     mutable bool m_needsGBKFallbacks;
+#endif
 };
 
 struct ICUConverterWrapper {
     WTF_MAKE_NONCOPYABLE(ICUConverterWrapper); WTF_MAKE_FAST_ALLOCATED(ICUConverterWrapper);
 public:
     ICUConverterWrapper() : converter(0) { }
     ~ICUConverterWrapper();
 
     UConverter* converter;
 };
 
 } // namespace WTF
 
 #endif // TextCodecICU_h