Scheme of content utils should be compared in an ASCII case-insensitive manner

Source/modules/navigatorcontentutils/NavigatorContentUtils.cpp

 /*
  * Copyright (C) 2011, Google Inc. All rights reserved.
  * Copyright (C) 2014, Samsung Electronics. All rights reserved.
  *
  * 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 16 matching lines @@
 #include "config.h"
 #include "modules/navigatorcontentutils/NavigatorContentUtils.h"
 
 #include "bindings/v8/ExceptionState.h"
 #include "core/dom/Document.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Navigator.h"
 #include "core/page/Page.h"
 #include "wtf/HashSet.h"
+#include "wtf/text/StringBuilder.h"
 
 namespace WebCore {
 
 static HashSet<String>* protocolWhitelist;
 
 static void initProtocolHandlerWhitelist()
 {
     protocolWhitelist = new HashSet<String>;
     static const char* const protocols[] = {
         "bitcoin",
@@ skipping 43 matching lines @@
         return false;
     }
 
     return true;
 }
 
 static bool isProtocolWhitelisted(const String& scheme)
 {
     if (!protocolWhitelist)
         initProtocolHandlerWhitelist();
-    return protocolWhitelist->contains(scheme);
+
+    StringBuilder builder;
+    unsigned length = scheme.length();
+    for (unsigned i = 0; i < length; ++i) {
+        UChar character = scheme[i];
+        if (isASCIIUpper(character))
+            builder.append(toASCIILower(character));
+        else
+            builder.append(character);

[haraken, 2014/06/07 02:19:23]

Do we need this branch? I guess builder.append(toASCIILower(character)) works as
expected for lower characters as well.

[gyuyoung-inactive, 2014/06/07 06:28:51]

Doesn't this operation always call toASCIILower() function even when character
is ASCII lowercase ? Of course, it looks it is trivial overhead.

[haraken, 2014/06/07 06:36:49]

I mean, you can remove line 106 - 109 and just use
builder.append(toASCIILower(character)).

The difference is just whether you check isASCIIUpper(character) in the caller
side or the callee side.

[gyuyoung-inactive, 2014/06/07 06:51:01]

Ah...yes. we can avoid to call isASCIIUpper() when using your suggestion.
Calling overhead looks same. 

+    }
+
+    return protocolWhitelist->contains(builder.toString());
 }
 
 static bool verifyProtocolHandlerScheme(const String& scheme, const String& method, ExceptionState& exceptionState)
 {
     if (scheme.startsWith("web+")) {
         // The specification requires that the length of scheme is at least five characteres (including 'web+' prefix).
         if (scheme.length() >= 5 && isValidProtocol(scheme))
             return true;
         if (!isValidProtocol(scheme))
             exceptionState.throwSecurityError("The scheme '" + scheme + "' is not a valid protocol.");
@@ skipping 112 matching lines @@
 {
     return "NavigatorContentUtils";
 }
 
 void provideNavigatorContentUtilsTo(Page& page, PassOwnPtr<NavigatorContentUtilsClient> client)
 {
     NavigatorContentUtils::provideTo(page, NavigatorContentUtils::supplementName(), NavigatorContentUtils::create(client));
 }
 
 } // namespace WebCore