DOM: Fix an incorrect result of getElementsByClassName() in quirks mode.

third_party/WebKit/Source/core/dom/ClassCollection.cpp

 /*
  * Copyright (C) 2007, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2007 David Smith (catfish.man@gmail.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.
@@ skipping 21 matching lines @@
 #include "core/dom/Document.h"
 #include "core/dom/NodeRareData.h"
 
 namespace blink {
 
 ClassCollection::ClassCollection(ContainerNode& root_node,
                                  const AtomicString& class_names)
     : HTMLCollection(root_node,
                      kClassCollectionType,
                      kDoesNotOverrideItemAfter),
-      class_names_(class_names,
-                   GetDocument().InQuirksMode()
-                       ? SpaceSplitString::kShouldFoldCase
-                       : SpaceSplitString::kShouldNotFoldCase),
-      original_class_names_(class_names) {}
+      class_names_(
+          GetDocument().InQuirksMode() ? class_names.LowerASCII() : class_names,
+          SpaceSplitString::kShouldNotFoldCase) {}
 
 ClassCollection::~ClassCollection() {}
 
 }  // namespace blink