Apply styles to mathML elements having class attribute.

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

Index: third_party/WebKit/Source/core/dom/Node.cpp
diff --git a/third_party/WebKit/Source/core/dom/Node.cpp b/third_party/WebKit/Source/core/dom/Node.cpp
index 5bc034fe69b6bc638690d634e74029c7670b5ca6..cb3954962fbf04a48be74a4bb182c668304093b4 100644
--- a/third_party/WebKit/Source/core/dom/Node.cpp
+++ b/third_party/WebKit/Source/core/dom/Node.cpp
@@ -29,6 +29,7 @@
 #include "bindings/core/v8/Microtask.h"
 #include "bindings/core/v8/V8DOMWrapper.h"
 #include "core/HTMLNames.h"
+#include "core/MathMLNames.h"
 #include "core/css/CSSSelector.h"
 #include "core/css/resolver/StyleResolver.h"
 #include "core/dom/AXObjectCache.h"
@@ -1029,6 +1030,19 @@ bool Node::canStartSelection() const
     return parent ? parent->canStartSelection() : true;
 }
 
+// StyledElements allow inline style (style="border: 1px"), presentational attributes (ex. color),
+// class names (ex. class="foo bar") and other non-basic styling features. They also control
+// if this element can participate in style sharing.
+//
+// FIXME: The only things that ever go through StyleResolver that aren't StyledElements are
+// PseudoElements and VTTElements. It's possible we can just eliminate all the checks
+// since those elements will never have class names, inline style, or other things that
+// this apparently guards against.
+bool Node::isStyledElement() const
+{
+    return isHTMLElement() || isSVGElement() || (isElementNode() && toElement(this)->namespaceURI() == MathMLNames::mathmlNamespaceURI);
+}
+
 bool Node::canParticipateInFlatTree() const
 {
     return !isShadowRoot() && !isSlotOrActiveInsertionPoint();