CSS will-change: Mentioning transform properties gives containing block

third_party/WebKit/Source/core/style/ComputedStyle.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 1212 matching lines @@
   }
   return false;
 }
 
 bool ComputedStyle::hasWillChangeTransformHint() const {
   for (const auto& property :
        m_rareNonInheritedData->m_willChange->m_properties) {
     switch (property) {
       case CSSPropertyTransform:
       case CSSPropertyAliasWebkitTransform:
+      case CSSPropertyPerspective:
+      case CSSPropertyTranslate:
+      case CSSPropertyScale:
+      case CSSPropertyRotate:
         return true;
       default:
         break;
     }
   }
   return false;
 }
 
 bool ComputedStyle::requireTransformOrigin(
     ApplyTransformOrigin applyOrigin,
@@ skipping 1107 matching lines @@
     if (value < 0)
       fvalue -= 0.5f;
     else
       fvalue += 0.5f;
   }
 
   return roundForImpreciseConversion<int>(fvalue / zoomFactor);
 }
 
 }  // namespace blink