Don't use cached inherited props for distributed nodes.

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 1339 matching lines @@
     bool applyInheritedOnly = false;
     const CachedMatchedProperties* cachedMatchedProperties = 0;
 
     if (cacheHash && (cachedMatchedProperties = m_matchedPropertiesCache.find(cacheHash, state, matchResult))
         && MatchedPropertiesCache::isCacheable(element, state.style(), state.parentStyle())) {
         INCREMENT_STYLE_STATS_COUNTER(*this, matchedPropertyCacheHit);
         // We can build up the style by copying non-inherited properties from an earlier style object built using the same exact
         // style declarations. We then only need to apply the inherited properties, if any, as their values can depend on the
         // element context. This is fast and saves memory by reusing the style data structures.
         state.style()->copyNonInheritedFrom(cachedMatchedProperties->renderStyle.get());
-        if (state.parentStyle()->inheritedDataShared(cachedMatchedProperties->parentRenderStyle.get()) && !isAtShadowBoundary(element)) {
+        if (state.parentStyle()->inheritedDataShared(cachedMatchedProperties->parentRenderStyle.get()) && !isAtShadowBoundary(element)
+            && (!state.distributedToInsertionPoint() || state.style()->userModify() == READ_ONLY)) {
             INCREMENT_STYLE_STATS_COUNTER(*this, matchedPropertyCacheInheritedHit);
 
             EInsideLink linkStatus = state.style()->insideLink();
             // If the cache item parent style has identical inherited properties to the current parent style then the
             // resulting style will be identical too. We copy the inherited properties over from the cache and are done.
             state.style()->inheritFrom(cachedMatchedProperties->renderStyle.get());
 
             // Unfortunately the link status is treated like an inherited property. We need to explicitly restore it.
             state.style()->setInsideLink(linkStatus);
             return;
@@ skipping 136 matching lines @@
 bool StyleResolver::mediaQueryAffectedByViewportChange() const
 {
     for (unsigned i = 0; i < m_viewportDependentMediaQueryResults.size(); ++i) {
         if (m_medium->eval(&m_viewportDependentMediaQueryResults[i]->m_expression) != m_viewportDependentMediaQueryResults[i]->m_result)
             return true;
     }
     return false;
 }
 
 } // namespace WebCore