[wip] simplify -webkit-appearance adjust step

Source/core/css/resolver/StyleResolver.cpp

 /*
  * 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.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
@@ skipping 575 matching lines @@
 
 static void addContentAttrValuesToFeatures(const Vector<AtomicString>& contentAttrValues, RuleFeatureSet& features)
 {
     for (size_t i = 0; i < contentAttrValues.size(); ++i)
         features.addContentAttr(contentAttrValues[i]);
 }
 
 void StyleResolver::adjustRenderStyle(StyleResolverState& state, Element* element)
 {
     StyleAdjuster adjuster(m_document.inQuirksMode());
-    adjuster.adjustRenderStyle(state.style(), state.parentStyle(), element, state.cachedUAStyle());
+    bool uaStyleHasWebkitAppearance = element && elementTypeHasAppearanceFromUAStyle(*element);
+    adjuster.adjustRenderStyle(state.style(), state.parentStyle(), element, uaStyleHasWebkitAppearance, state.valuesUnchangedForWebkitAppearance());
 }
 
 // Start loading resources referenced by this style.
 void StyleResolver::loadPendingResources(StyleResolverState& state)
 {
     m_styleResourceLoader.loadPendingResources(state.style(), state.elementStyleResources());
     document().styleEngine()->fontSelector()->fontLoader()->loadPendingFonts();
 }
 
 PassRefPtr<RenderStyle> StyleResolver::styleForElement(Element* element, RenderStyle* defaultParent, StyleSharingBehavior sharingBehavior,
@@ skipping 551 matching lines @@
 
     // If our font got dirtied, go ahead and update it now.
     updateFont(state);
 
     // Many properties depend on the font. If it changes we just apply all properties.
     if (cachedMatchedProperties && cachedMatchedProperties->renderStyle->fontDescription() != state.style()->fontDescription())
         applyInheritedOnly = false;
 
     // This code supports -webkit-appearance, for which we are interested
     // in whether the user has specified border or background properties.
-    // FIXME: This is a bit of a mess, we should just compare CSSValues and
-    // store a single bit for this.
     if (elementTypeHasAppearanceFromUAStyle(*element)) {
-        CascadedValues userAgentValues(state, matchResult, true);
-        // We only actually care about border and background properties here
-        userAgentValues.applyValues(firstCSSPropertyId<LowPriorityProperties>(), lastCSSPropertyId<LowPriorityProperties>(), applyInheritedOnly);
-        state.cacheUserAgentBorderAndBackground();
+        if (cascadedValues.valuesUnchangedForWebkitAppearance(matchResult))
+            state.setValuesUnchangedForWebkitAppearance();
     }
 
     cascadedValues.applyValues(firstCSSPropertyId<LowPriorityProperties>(), lastCSSPropertyId<LowPriorityProperties>(), applyInheritedOnly);
 
     loadPendingResources(state);
 
     if (!cachedMatchedProperties && cacheHash && MatchedPropertiesCache::isCacheable(element, state.style(), state.parentStyle())) {
         INCREMENT_STYLE_STATS_COUNTER(*this, matchedPropertyCacheAdded);
         m_matchedPropertiesCache.add(state.style(), state.parentStyle(), cacheHash, matchResult);
     }
@@ skipping 84 matching lines @@
     visitor->trace(m_features);
     visitor->trace(m_siblingRuleSet);
     visitor->trace(m_uncommonAttributeRuleSet);
     visitor->trace(m_watchedSelectorsRules);
     visitor->trace(m_treeBoundaryCrossingRules);
     visitor->trace(m_pendingStyleSheets);
 #endif
 }
 
 } // namespace blink