Fix class name which has only space

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2013 Apple Inc.
  * All rights reserved.
  *           (C) 2007 Eric Seidel (eric@webkit.org)
  *
@@ skipping 1359 matching lines @@
   const bool shouldFoldCase = document().inQuirksMode();
   if (classStringContentType == ClassStringContent::HasClasses) {
     const SpaceSplitString oldClasses = elementData()->classNames();
     elementData()->setClass(newClassString, shouldFoldCase);
     const SpaceSplitString& newClasses = elementData()->classNames();
     document().styleEngine().classChangedForElement(oldClasses, newClasses,
                                                     *this);
   } else {
     const SpaceSplitString& oldClasses = elementData()->classNames();
     document().styleEngine().classChangedForElement(oldClasses, *this);
-    if (classStringContentType == ClassStringContent::WhiteSpaceOnly)
-      elementData()->setClass(newClassString, shouldFoldCase);
-    else
-      elementData()->clearClass();
+    elementData()->setClass(newClassString, shouldFoldCase);

[skobes, 2016/10/14 20:41:30]

I don't quite understand how this works.  Setting class=" " seems like it should
produce classStringContentType == WhiteSpaceOnly, but this only changes the
logic for classStringContentType == Empty?

   }
 
   if (hasRareData())
     elementRareData()->clearClassListValueForQuirksMode();
 }
 
 bool Element::shouldInvalidateDistributionWhenAttributeChanged(
     ElementShadow* elementShadow,
     const QualifiedName& name,
     const AtomicString& newValue) {
@@ skipping 2688 matching lines @@
 }
 
 DEFINE_TRACE_WRAPPERS(Element) {
   if (hasRareData()) {
     visitor->traceWrappers(elementRareData());
   }
   ContainerNode::traceWrappers(visitor);
 }
 
 }  // namespace blink