replace COMPILE_ASSERT with static assert in wtf/

Source/wtf/StringHasher.h

 /*
  * Copyright (C) 2005, 2006, 2008, 2010, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Patrick Gansterer <paroga@paroga.com>
  *
  * 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 173 matching lines @@
     {
         // FIXME: Why does this function use the version of the hash that drops the top 8 bits?
         // We want that for all string hashing so we can use those bits in StringImpl and hash
         // strings consistently, but I don't see why we'd want that for general memory hashing.
         ASSERT(!(length % 2));
         return computeHashAndMaskTop8Bits<UChar>(static_cast<const UChar*>(data), length / sizeof(UChar));
     }
 
     template<size_t length> static unsigned hashMemory(const void* data)
     {
-        COMPILE_ASSERT(!(length % 2), length_must_be_a_multiple_of_two);
+        static_assert(!(length % 2), "length must be a multiple of two");
         return hashMemory(data, length);
     }
 
 private:
     static UChar defaultConverter(UChar character)
     {
         return character;
     }
 
     static UChar defaultConverter(LChar character)
@@ skipping 25 matching lines @@
     unsigned m_hash;
     bool m_hasPendingCharacter;
     UChar m_pendingCharacter;
 };
 
 } // namespace WTF
 
 using WTF::StringHasher;
 
 #endif // WTF_StringHasher_h