Marquee width should not change a fixed width of its container.

Source/core/html/HTMLMarqueeElement.cpp

Index: Source/core/html/HTMLMarqueeElement.cpp
diff --git a/Source/core/html/HTMLMarqueeElement.cpp b/Source/core/html/HTMLMarqueeElement.cpp
index a0d7155fc2dae621d930e2f32d0627de46b9b135..418e088f0c2afa2a1803d1df274df4774e168b90 100644
--- a/Source/core/html/HTMLMarqueeElement.cpp
+++ b/Source/core/html/HTMLMarqueeElement.cpp
@@ -71,4 +71,10 @@ void HTMLMarqueeElement::removedFrom(ContainerNode* insertionPoint)
     }
 }
 
+bool HTMLMarqueeElement::isHorizontal() const
+{
+    AtomicString direction = getAttribute(HTMLNames::directionAttr);
+    return direction != "down" && direction != "up";
+}
+
 } // namespace blink