Count element name validity per DOM versus HTML parsing.

third_party/WebKit/Source/core/paint/PaintLayerScrollableAreaTest.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/paint/PaintLayerScrollableArea.h"
 
 #include "core/frame/FrameView.h"
 #include "core/layout/LayoutBoxModelObject.h"
 #include "core/layout/LayoutTestHelper.h"
 #include "core/paint/PaintLayer.h"
@@ skipping 497 matching lines @@
       "<div id=\"scroller\"><div id=\"scrolled\"></div></div>");
   GetDocument().View()->UpdateAllLifecyclePhases();
 
   Element* scroller = GetDocument().GetElementById("scroller");
   PaintLayer* paint_layer =
       ToLayoutBoxModelObject(scroller->GetLayoutObject())->Layer();
   ASSERT_TRUE(paint_layer);
   EXPECT_TRUE(paint_layer->NeedsCompositedScrolling());
 
   // Add clip to scroller.
-  scroller->setAttribute("class", "clip", ASSERT_NO_EXCEPTION);
+  scroller->setAttribute(HTMLNames::classAttr, "clip");
   GetDocument().View()->UpdateAllLifecyclePhases();
   paint_layer = ToLayoutBoxModelObject(scroller->GetLayoutObject())->Layer();
   ASSERT_TRUE(paint_layer);
   EXPECT_FALSE(paint_layer->NeedsCompositedScrolling());
 
   // Change the scroller to be auto clipped again.
   scroller->removeAttribute("class");
   GetDocument().View()->UpdateAllLifecyclePhases();
   paint_layer = ToLayoutBoxModelObject(scroller->GetLayoutObject())->Layer();
   ASSERT_TRUE(paint_layer);
@@ skipping 93 matching lines @@
       "</div>");
   GetDocument().View()->UpdateAllLifecyclePhases();
   Element* container = GetDocument().GetElementById("container");
   ASSERT_TRUE(container);
   PaintLayerScrollableArea* scrollable_area =
       ToLayoutBoxModelObject(container->GetLayoutObject())->GetScrollableArea();
   ASSERT_TRUE(scrollable_area);
   EXPECT_FALSE(scrollable_area->HasHorizontalScrollbar());
 }
 }