Use StringView for equalIgnoringCase.

third_party/WebKit/Source/wtf/text/StringHash.h

 /*
  * Copyright (C) 2006, 2007, 2008, 2012, 2013 Apple Inc. All rights reserved
  * Copyright (C) Research In Motion Limited 2009. 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 80 matching lines @@
         return CaseFoldingHash::hash(reinterpret_cast<const LChar*>(data), length);
     }
 
     static inline unsigned hash(const char* data)
     {
         return CaseFoldingHash::hash(reinterpret_cast<const LChar*>(data), strlen(data));
     }
 
     static inline bool equal(const StringImpl* a, const StringImpl* b)
     {
-        return equalIgnoringCaseNonNull(a, b);
+        DCHECK(a);
+        DCHECK(b);
+        // Save one branch inside each StringView by derefing the StringImpl,
+        // and another branch inside the compare function by skipping the null
+        // checks.
+        return equalIgnoringCaseAndNullity(*a, *b);
     }
 
     static unsigned hash(const RefPtr<StringImpl>& key)
     {
         return hash(key.get());
     }
 
     static bool equal(const RefPtr<StringImpl>& a, const RefPtr<StringImpl>& b)
     {
         return equal(a.get(), b.get());
@@ skipping 54 matching lines @@
     }
 };
 
 } // namespace WTF
 
 using WTF::AlreadyHashed;
 using WTF::CaseFoldingHash;
 using WTF::StringHash;
 
 #endif