Prevent will-change:transform from changing the computed value of transform

Source/core/css/resolver/StyleAdjuster.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 183 matching lines @@
         || style.clipPath()
         || style.boxReflect()
         || style.hasFilter()
         || style.hasBlendMode()
         || style.hasIsolation()
         || style.position() == FixedPosition
         || isInTopLayer(e, style)
         || hasWillChangeThatCreatesStackingContext(style)))
         style.setZIndex(0);
 
-    // will-change:transform should result in the same rendering behavior as having a transform,
-    // including the creation of a containing block for fixed position descendants.
-    // SVG elements can skip this because they implicitly have transforms.
-    bool isSVGElement = e && e->isSVGElement();
-    if (!isSVGElement && !style.hasTransform() && (style.willChangeProperties().contains(CSSPropertyAliasWebkitTransform) || style.willChangeProperties().contains(CSSPropertyTransform))) {
-        bool makeIdentity = true;
-        style.setTransform(TransformOperations(makeIdentity));
-    }
-
     if (doesNotInheritTextDecoration(style, e))
         style.clearAppliedTextDecorations();
 
     style.applyTextDecorations();
 
     if (style.overflowX() != OVISIBLE || style.overflowY() != OVISIBLE)
         adjustOverflow(style);
 
     // Cull out any useless layers and also repeat patterns into additional layers.
     style.adjustBackgroundLayers();
     style.adjustMaskLayers();
 
     // Let the theme also have a crack at adjusting the style.
     if (style.hasAppearance())
         LayoutTheme::theme().adjustStyle(style, e, authorStyle);
 
     // If we have first-letter pseudo style, transitions, or animations, do not share this style.
     if (style.hasPseudoStyle(FIRST_LETTER) || style.transitions() || style.animations())
         style.setUnique();
 
     // FIXME: when dropping the -webkit prefix on transform-style, we should also have opacity < 1 cause flattening.
     if (style.preserves3D() && (style.overflowX() != OVISIBLE
         || style.overflowY() != OVISIBLE
         || style.hasFilter()))
         style.setTransformStyle3D(TransformStyle3DFlat);
 
+    bool isSVGElement = e && e->isSVGElement();
     if (isSVGElement) {
         // Only the root <svg> element in an SVG document fragment tree honors css position
         if (!(isSVGSVGElement(*e) && e->parentNode() && !e->parentNode()->isSVGElement()))
             style.setPosition(ComputedStyle::initialPosition());
 
         // SVG text layout code expects us to be a block-level style element.
         if ((isSVGForeignObjectElement(*e) || isSVGTextElement(*e)) && style.isDisplayInlineType())
             style.setDisplay(BLOCK);
 
         // Columns don't apply to svg text elements.
@@ skipping 245 matching lines @@
     if (style.writingMode() != TopToBottomWritingMode && (style.display() == BOX || style.display() == INLINE_BOX))
         style.setWritingMode(TopToBottomWritingMode);
 
     if (parentStyle.isDisplayFlexibleOrGridBox()) {
         style.setFloating(NoFloat);
         style.setDisplay(equivalentBlockDisplay(style.display(), style.isFloating(), !m_useQuirksModeStyles));
     }
 }
 
 }