Implement will-change-based creation of layers, stacking contexts, and containing blocks

Source/core/rendering/style/RenderStyle.cpp

 /*
  * Copyright (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2011 Adobe Systems Incorporated. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 632 matching lines @@
             return StyleDifferenceRepaint;
 
         if (rareNonInheritedData->m_clipPath != other->rareNonInheritedData->m_clipPath)
             return StyleDifferenceRepaint;
 
     if (rareNonInheritedData.get() != other->rareNonInheritedData.get()) {
         if (rareNonInheritedData->m_transformStyle3D != other->rareNonInheritedData->m_transformStyle3D
             || rareNonInheritedData->m_backfaceVisibility != other->rareNonInheritedData->m_backfaceVisibility
             || rareNonInheritedData->m_perspective != other->rareNonInheritedData->m_perspective
             || rareNonInheritedData->m_perspectiveOriginX != other->rareNonInheritedData->m_perspectiveOriginX
-            || rareNonInheritedData->m_perspectiveOriginY != other->rareNonInheritedData->m_perspectiveOriginY)
+            || rareNonInheritedData->m_perspectiveOriginY != other->rareNonInheritedData->m_perspectiveOriginY
+            || hasWillChangeCompositingHint() != other->hasWillChangeCompositingHint())
             return StyleDifferenceRecompositeLayer;
     }
 
     if (inherited->color != other->inherited->color
         || inherited_flags._text_decorations != other->inherited_flags._text_decorations
         || visual->textDecoration != other->visual->textDecoration
         || rareNonInheritedData->m_textDecorationStyle != other->rareNonInheritedData->m_textDecorationStyle
         || rareNonInheritedData->m_textDecorationColor != other->rareNonInheritedData->m_textDecorationColor
         || rareInheritedData->textFillColor != other->rareInheritedData->textFillColor
         || rareInheritedData->textStrokeColor != other->rareInheritedData->textStrokeColor
@@ skipping 160 matching lines @@
         rareNonInheritedData.access()->m_isolation = v;
 }
 
 bool RenderStyle::hasIsolation() const
 {
     if (RuntimeEnabledFeatures::cssCompositingEnabled())
         return rareNonInheritedData->m_isolation != IsolationAuto;
     return false;
 }
 
+bool RenderStyle::hasWillChangeCompositingHint() const
+{
+    for (size_t i = 0; i < rareNonInheritedData->m_willChange->m_properties.size(); ++i) {
+        switch (rareNonInheritedData->m_willChange->m_properties[i]) {
+        case CSSPropertyOpacity:
+        case CSSPropertyWebkitTransform:
+        case CSSPropertyLeft:
+        case CSSPropertyTop:
+        case CSSPropertyRight:
+        case CSSPropertyBottom:
+        case CSSPropertyWebkitFilter:
+            return true;
+        default:
+            break;
+        }
+    }
+    return false;
+}
+
 inline bool requireTransformOrigin(const Vector<RefPtr<TransformOperation> >& transformOperations, RenderStyle::ApplyTransformOrigin applyOrigin)
 {
     // transform-origin brackets the transform with translate operations.
     // Optimize for the case where the only transform is a translation, since the transform-origin is irrelevant
     // in that case.
     if (applyOrigin != RenderStyle::IncludeTransformOrigin)
         return false;
 
     unsigned size = transformOperations.size();
     for (unsigned i = 0; i < size; ++i) {
@@ skipping 755 matching lines @@
 }
 
 void RenderStyle::setBorderImageOutset(const BorderImageLengthBox& outset)
 {
     if (surround->border.m_image.outset() == outset)
         return;
     surround.access()->border.m_image.setOutset(outset);
 }
 
 } // namespace WebCore