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

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

Index: third_party/WebKit/Source/core/dom/ClassCollection.cpp
diff --git a/third_party/WebKit/Source/core/dom/ClassCollection.cpp b/third_party/WebKit/Source/core/dom/ClassCollection.cpp
index 4e78bc905f1fbd76a4abfca5eeb642683c1b9205..e44ca17d53269fde9e4b698122f9af2db92015c7 100644
--- a/third_party/WebKit/Source/core/dom/ClassCollection.cpp
+++ b/third_party/WebKit/Source/core/dom/ClassCollection.cpp
@@ -39,11 +39,9 @@ ClassCollection::ClassCollection(ContainerNode& root_node,
     : 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() {}