Optimize for horizontal writing mode

Source/core/css/resolver/StyleBuilderCustom.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
@@ skipping 879 matching lines @@
         return;
     const CSSPrimitiveValue* primitiveValue = toCSSPrimitiveValue(value);
     if (!primitiveValue->getValueID())
         return;
     state.style()->setDraggableRegionMode(primitiveValue->getValueID() == CSSValueDrag ? DraggableRegionDrag : DraggableRegionNoDrag);
     state.document().setHasAnnotatedRegions(true);
 }
 
 void StyleBuilderFunctions::applyValueCSSPropertyWebkitWritingMode(StyleResolverState& state, CSSValue* value)
 {
-    if (value->isPrimitiveValue())
-        state.setWritingMode(*toCSSPrimitiveValue(value));
+    if (value->isPrimitiveValue()) {
+        CSSPrimitiveValue* primitiveValue = toCSSPrimitiveValue(value);
+        state.setWritingMode(*primitiveValue);
+        if (!isHorizontalWritingMode(*primitiveValue))
+            state.document().setContainsAnyVerticalWritingModes(true);
+    }
 
     // FIXME: It is not ok to modify document state while applying style.
     if (state.element() && state.element() == state.document().documentElement())
         state.document().setWritingModeSetOnDocumentElement(true);
 }
 
 void StyleBuilderFunctions::applyValueCSSPropertyWebkitTextOrientation(StyleResolverState& state, CSSValue* value)
 {
     if (value->isPrimitiveValue())
         state.setTextOrientation(*toCSSPrimitiveValue(value));
@@ skipping 27 matching lines @@
         return;
     case CSSValueSuper:
         svgStyle.setBaselineShift(BS_SUPER);
         return;
     default:
         ASSERT_NOT_REACHED();
     }
 }
 
 } // namespace blink