Merge 98492 - REGRESSION (r94887): Scrolling the HTML spec is more jerky now than it was (regress...

Source/WebCore/css/CSSStyleSelector.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 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 871 matching lines @@
 
     if (isControl != m_element->isFormControlElement())
         return false;
 
     if (isControl && !canShareStyleWithControl(element))
         return false;
 
     if (style->transitions() || style->animations())
         return false;
 
-    if (style->affectedByDirectAdjacentRules())
-        return false;
-
 #if USE(ACCELERATED_COMPOSITING)
     // Turn off style sharing for elements that can gain layers for reasons outside of the style system.
     // See comments in RenderObject::setStyle().
     if (element->hasTagName(iframeTag) || element->hasTagName(frameTag) || element->hasTagName(embedTag) || element->hasTagName(objectTag) || element->hasTagName(appletTag))
         return false;
 #endif
 
     if (equalIgnoringCase(element->fastGetAttribute(dirAttr), "auto") || equalIgnoringCase(m_element->fastGetAttribute(dirAttr), "auto"))
         return false;
 
@@ skipping 19 matching lines @@
         if (count++ == cStyleSearchThreshold)
             return 0;
     }
     return node;
 }
 
 static inline bool parentStylePreventsSharing(const RenderStyle* parentStyle)
 {
     return parentStyle->childrenAffectedByPositionalRules() 
         || parentStyle->childrenAffectedByFirstChildRules()
-        || parentStyle->childrenAffectedByLastChildRules();
+        || parentStyle->childrenAffectedByLastChildRules() 
+        || parentStyle->childrenAffectedByDirectAdjacentRules();
 }
 
 RenderStyle* CSSStyleSelector::locateSharedStyle()
 {
     if (!m_styledElement || !m_parentStyle)
         return 0;
     // If the element has inline style it is probably unique.
     if (m_styledElement->inlineStyleDecl())
         return 0;
     // Ids stop style sharing if they show up in the stylesheets.
@@ skipping 4556 matching lines @@
             }
             default:
                 ASSERT_NOT_REACHED();
         }
     }
 
     m_pendingImageProperties.clear();
 }
 
 } // namespace WebCore