InPrePaint document state and PrePaintTreeWalk class

third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/paint/PaintPropertyTreeBuilder.h"
 
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
 #include "core/layout/LayoutInline.h"
 #include "core/layout/LayoutPart.h"
 #include "core/paint/ObjectPaintProperties.h"
 #include "core/paint/PaintLayer.h"
 #include "platform/graphics/paint/ClipPaintPropertyNode.h"
 #include "platform/graphics/paint/TransformPaintPropertyNode.h"
 #include "platform/transforms/TransformationMatrix.h"
 
 namespace blink {
 
-// The context for layout tree walk.
-// The walk will be done in the primary tree order (= DOM order), thus the context will also be
-// responsible for bookkeeping tree state in other order, for example, the most recent position
-// container seen.
-struct PaintPropertyTreeBuilderContext {
-    PaintPropertyTreeBuilderContext()
-        : currentTransform(nullptr)
-        , currentClip(nullptr)
-        , transformForAbsolutePosition(nullptr)
-        , containerForAbsolutePosition(nullptr)
-        , clipForAbsolutePosition(nullptr)
-        , transformForFixedPosition(nullptr)
-        , clipForFixedPosition(nullptr)
-        , currentEffect(nullptr) { }
-
-    // The combination of a transform and paint offset describes a linear space.
-    // When a layout object recur to its children, the main context is expected to refer
-    // the object's border box, then the callee will derive its own border box by translating
-    // the space with its own layout location.
-    TransformPaintPropertyNode* currentTransform;
-    LayoutPoint paintOffset;
-    // The clip node describes the accumulated raster clip for the current subtree.
-    // Note that the computed raster region in canvas space for a clip node is independent from
-    // the transform and paint offset above. Also the actual raster region may be affected
-    // by layerization and occlusion tracking.
-    ClipPaintPropertyNode* currentClip;
-
-    // Separate context for out-of-flow positioned and fixed positioned elements are needed
-    // because they don't use DOM parent as their containing block.
-    // These additional contexts normally pass through untouched, and are only copied from
-    // the main context when the current element serves as the containing block of corresponding
-    // positioned descendants.
-    // Overflow clips are also inherited by containing block tree instead of DOM tree, thus they
-    // are included in the additional context too.
-    TransformPaintPropertyNode* transformForAbsolutePosition;
-    LayoutPoint paintOffsetForAbsolutePosition;
-    LayoutObject* containerForAbsolutePosition;
-    ClipPaintPropertyNode* clipForAbsolutePosition;
-
-    TransformPaintPropertyNode* transformForFixedPosition;
-    LayoutPoint paintOffsetForFixedPosition;
-    ClipPaintPropertyNode* clipForFixedPosition;
-
-    // The effect hierarchy is applied by the stacking context tree. It is guaranteed that every
-    // DOM descendant is also a stacking context descendant. Therefore, we don't need extra
-    // bookkeeping for effect nodes and can generate the effect tree from a DOM-order traversal.
-    EffectPaintPropertyNode* currentEffect;
-};
-
-void PaintPropertyTreeBuilder::buildPropertyTrees(FrameView& rootFrame)
+void PaintPropertyTreeBuilder::buildTreeRootNodes(FrameView& rootFrame, PaintPropertyTreeBuilderRootContext& rootContext)
 {
-    PaintPropertyTreeBuilderContext rootContext;
-
-    // We don't retain permanent reference of these nodes except by child nodes.
-    // Keeps local reference until the walk finishes.
-    RefPtr<TransformPaintPropertyNode> transformRoot;
-    RefPtr<ClipPaintPropertyNode> clipRoot;
-    RefPtr<EffectPaintPropertyNode> effectRoot;
-
     // Only create extra root clip and transform nodes when RLS is enabled, because the main frame
     // unconditionally create frame translation / clip nodes otherwise.
     if (rootFrame.frame().settings() && rootFrame.frame().settings()->rootLayerScrolls()) {
-        transformRoot = TransformPaintPropertyNode::create(TransformationMatrix(), FloatPoint3D(), nullptr);
-        rootContext.currentTransform = rootContext.transformForAbsolutePosition = rootContext.transformForFixedPosition = transformRoot.get();
+        rootContext.transformRoot = TransformPaintPropertyNode::create(TransformationMatrix(), FloatPoint3D(), nullptr);
+        rootContext.currentTransform = rootContext.transformForAbsolutePosition = rootContext.transformForFixedPosition = rootContext.transformRoot.get();
 
-        clipRoot = ClipPaintPropertyNode::create(transformRoot, FloatRoundedRect(LayoutRect::infiniteIntRect()), nullptr);
-        rootContext.currentClip = rootContext.clipForAbsolutePosition = rootContext.clipForFixedPosition = clipRoot.get();
+        rootContext.clipRoot = ClipPaintPropertyNode::create(rootContext.transformRoot, FloatRoundedRect(LayoutRect::infiniteIntRect()), nullptr);
+        rootContext.currentClip = rootContext.clipForAbsolutePosition = rootContext.clipForFixedPosition = rootContext.clipRoot.get();
     }
 
     // The root frame never creates effect node so we unconditionally create a root node here.
-    effectRoot = EffectPaintPropertyNode::create(1.0, nullptr);
-    rootContext.currentEffect = effectRoot.get();
-
-    walk(rootFrame, rootContext);
+    rootContext.effectRoot = EffectPaintPropertyNode::create(1.0, nullptr);
+    rootContext.currentEffect = rootContext.effectRoot.get();
 }
 
-void PaintPropertyTreeBuilder::walk(FrameView& frameView, const PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::buildTreeNodes(FrameView& frameView, PaintPropertyTreeBuilderContext& context)
 {
-    PaintPropertyTreeBuilderContext localContext(context);
-
     // TODO(pdr): Creating paint properties for FrameView here will not be
     // needed once settings()->rootLayerScrolls() is enabled.
     // TODO(pdr): Make this conditional on the rootLayerScrolls setting.
 
     TransformationMatrix frameTranslate;
     frameTranslate.translate(frameView.x() + context.paintOffset.x(), frameView.y() + context.paintOffset.y());
     RefPtr<TransformPaintPropertyNode> newTransformNodeForPreTranslation = TransformPaintPropertyNode::create(frameTranslate, FloatPoint3D(), context.currentTransform);
-    localContext.transformForFixedPosition = newTransformNodeForPreTranslation.get();
-    localContext.paintOffsetForFixedPosition = LayoutPoint();
+    context.transformForFixedPosition = newTransformNodeForPreTranslation.get();
+    context.paintOffsetForFixedPosition = LayoutPoint();
 
     FloatRoundedRect contentClip(IntRect(IntPoint(), frameView.visibleContentSize()));
-    RefPtr<ClipPaintPropertyNode> newClipNodeForContentClip = ClipPaintPropertyNode::create(newTransformNodeForPreTranslation.get(), contentClip, localContext.currentClip);
-    localContext.currentClip = localContext.clipForAbsolutePosition = localContext.clipForFixedPosition = newClipNodeForContentClip.get();
+    RefPtr<ClipPaintPropertyNode> newClipNodeForContentClip = ClipPaintPropertyNode::create(newTransformNodeForPreTranslation.get(), contentClip, context.currentClip);
+    context.currentClip = context.clipForAbsolutePosition = context.clipForFixedPosition = newClipNodeForContentClip.get();
 
     DoubleSize scrollOffset = frameView.scrollOffsetDouble();
     TransformationMatrix frameScroll;
     frameScroll.translate(-scrollOffset.width(), -scrollOffset.height());
     RefPtr<TransformPaintPropertyNode> newTransformNodeForScrollTranslation = TransformPaintPropertyNode::create(frameScroll, FloatPoint3D(), newTransformNodeForPreTranslation);
-    localContext.currentTransform = localContext.transformForAbsolutePosition = newTransformNodeForScrollTranslation.get();
-    localContext.paintOffset = LayoutPoint();
-    localContext.paintOffsetForAbsolutePosition = LayoutPoint();
-    localContext.containerForAbsolutePosition = nullptr;
+    context.currentTransform = context.transformForAbsolutePosition = newTransformNodeForScrollTranslation.get();
+    context.paintOffset = LayoutPoint();
+    context.paintOffsetForAbsolutePosition = LayoutPoint();
+    context.containerForAbsolutePosition = nullptr;
 
     frameView.setPreTranslation(newTransformNodeForPreTranslation.release());
     frameView.setScrollTranslation(newTransformNodeForScrollTranslation.release());
     frameView.setContentClip(newClipNodeForContentClip.release());
-
-    if (LayoutView* layoutView = frameView.layoutView())
-        walk(*layoutView, localContext);
 }
 
-void PaintPropertyTreeBuilder::updatePaintOffsetTranslation(LayoutObject& object, PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::updatePaintOffsetTranslation(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
     bool shouldCreatePaintOffsetTranslationNode = false;
     if (object.isSVGRoot()) {
         // SVG doesn't use paint offset internally so emit a paint offset at the html->svg boundary.
         shouldCreatePaintOffsetTranslationNode = true;
     } else if (object.isBoxModelObject()) {
         // TODO(trchen): Eliminate PaintLayer dependency.
         PaintLayer* layer = toLayoutBoxModelObject(object).layer();
         shouldCreatePaintOffsetTranslationNode = layer && layer->paintsWithTransform(GlobalPaintNormalPhase);
     }
 
     if (context.paintOffset == LayoutPoint() || !shouldCreatePaintOffsetTranslationNode)
         return;
 
     RefPtr<TransformPaintPropertyNode> paintOffsetTranslation = TransformPaintPropertyNode::create(
         TransformationMatrix().translate(context.paintOffset.x(), context.paintOffset.y()),
         FloatPoint3D(), context.currentTransform);
     context.currentTransform = paintOffsetTranslation.get();
     context.paintOffset = LayoutPoint();
-    object.ensureObjectPaintProperties().setPaintOffsetTranslation(paintOffsetTranslation.release());
+    object.getMutableForPainting().ensureObjectPaintProperties().setPaintOffsetTranslation(paintOffsetTranslation.release());
 }
 
 static FloatPoint3D transformOrigin(const LayoutBox& box)
 {
     const ComputedStyle& style = box.styleRef();
     FloatSize borderBoxSize(box.size());
     return FloatPoint3D(
         floatValueForLength(style.transformOriginX(), borderBoxSize.width()),
         floatValueForLength(style.transformOriginY(), borderBoxSize.height()),
         style.transformOriginZ());
 }
 
-void PaintPropertyTreeBuilder::updateTransform(LayoutObject& object, PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::updateTransform(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
     const ComputedStyle& style = object.styleRef();
     if (!object.isBox() || !style.hasTransform())
         return;
     ASSERT(context.paintOffset == LayoutPoint());
 
     TransformationMatrix matrix;
     style.applyTransform(matrix, toLayoutBox(object).size(), ComputedStyle::ExcludeTransformOrigin,
         ComputedStyle::IncludeMotionPath, ComputedStyle::IncludeIndependentTransformProperties);
     RefPtr<TransformPaintPropertyNode> transformNode = TransformPaintPropertyNode::create(
         matrix, transformOrigin(toLayoutBox(object)), context.currentTransform);
     context.currentTransform = transformNode.get();
-    object.ensureObjectPaintProperties().setTransform(transformNode.release());
+    object.getMutableForPainting().ensureObjectPaintProperties().setTransform(transformNode.release());
 }
 
-void PaintPropertyTreeBuilder::updateEffect(LayoutObject& object, PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::updateEffect(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
     if (!object.styleRef().hasOpacity())
         return;
     RefPtr<EffectPaintPropertyNode> effectNode = EffectPaintPropertyNode::create(object.styleRef().opacity(), context.currentEffect);
     context.currentEffect = effectNode.get();
-    object.ensureObjectPaintProperties().setEffect(effectNode.release());
+    object.getMutableForPainting().ensureObjectPaintProperties().setEffect(effectNode.release());
 }
 
-void PaintPropertyTreeBuilder::updateCssClip(LayoutObject& object, PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::updateCssClip(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
     if (!object.hasClip())
         return;
     ASSERT(object.canContainAbsolutePositionObjects());
 
     // Create clip node for descendants that are not fixed position.
     // We don't have to setup context.clipForAbsolutePosition here because this object must be
     // a container for absolute position descendants, and will copy from in-flow context later
     // at updateOutOfFlowContext() step.
     LayoutRect clipRect = toLayoutBox(object).clipRect(context.paintOffset);
     RefPtr<ClipPaintPropertyNode> clipNode = ClipPaintPropertyNode::create(
         context.currentTransform,
         FloatRoundedRect(FloatRect(clipRect)),
         context.currentClip);
     context.currentClip = clipNode.get();
-    object.ensureObjectPaintProperties().setCssClip(clipNode.release());
+    object.getMutableForPainting().ensureObjectPaintProperties().setCssClip(clipNode.release());
 }
 
-void PaintPropertyTreeBuilder::updateLocalBorderBoxContext(LayoutObject& object, const PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::updateLocalBorderBoxContext(const LayoutObject& object, const PaintPropertyTreeBuilderContext& context)
 {
     // Note: Currently only layer painter makes use of the pre-computed context.
     // This condition may be loosened with no adverse effects beside memory use.
     if (!object.hasLayer())
         return;
 
     OwnPtr<ObjectPaintProperties::LocalBorderBoxProperties> borderBoxContext =
         adoptPtr(new ObjectPaintProperties::LocalBorderBoxProperties);
     borderBoxContext->paintOffset = context.paintOffset;
     borderBoxContext->transform = context.currentTransform;
     borderBoxContext->clip = context.currentClip;
     borderBoxContext->effect = context.currentEffect;
-    object.ensureObjectPaintProperties().setLocalBorderBoxProperties(std::move(borderBoxContext));
+    object.getMutableForPainting().ensureObjectPaintProperties().setLocalBorderBoxProperties(std::move(borderBoxContext));
 }
 
 // TODO(trchen): Remove this once we bake the paint offset into frameRect.
-void PaintPropertyTreeBuilder::updateScrollbarPaintOffset(LayoutObject& object, const PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::updateScrollbarPaintOffset(const LayoutObject& object, const PaintPropertyTreeBuilderContext& context)
 {
     IntPoint roundedPaintOffset = roundedIntPoint(context.paintOffset);
     if (roundedPaintOffset == IntPoint())
         return;
 
     if (!object.isBoxModelObject())
         return;
     PaintLayerScrollableArea* scrollableArea = toLayoutBoxModelObject(object).getScrollableArea();
     if (!scrollableArea)
         return;
     if (!scrollableArea->horizontalScrollbar() && !scrollableArea->verticalScrollbar())
         return;
 
     auto paintOffset = TransformationMatrix().translate(roundedPaintOffset.x(), roundedPaintOffset.y());
-    object.ensureObjectPaintProperties().setScrollbarPaintOffset(
+    object.getMutableForPainting().ensureObjectPaintProperties().setScrollbarPaintOffset(
         TransformPaintPropertyNode::create(paintOffset, FloatPoint3D(), context.currentTransform));
 }
 
-void PaintPropertyTreeBuilder::updateOverflowClip(LayoutObject& object, PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::updateOverflowClip(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
     if (!object.isBox())
         return;
     const LayoutBox& box = toLayoutBox(object);
 
     // The <input> elements can't have contents thus CSS overflow property doesn't apply.
     // However for layout purposes we do generate child layout objects for them, e.g. button label.
     // We should clip the overflow from those children. This is called control clip and we
     // technically treat them like overflow clip.
     LayoutRect clipRect;
@@ skipping 10 matching lines @@
             LayoutRect(context.paintOffset, box.size()));
         borderRadiusClip = ClipPaintPropertyNode::create(
             context.currentTransform, innerBorder, context.currentClip);
     }
 
     RefPtr<ClipPaintPropertyNode> overflowClip = ClipPaintPropertyNode::create(
         context.currentTransform,
         FloatRoundedRect(FloatRect(clipRect)),
         borderRadiusClip ? borderRadiusClip.release() : context.currentClip);
     context.currentClip = overflowClip.get();
-    object.ensureObjectPaintProperties().setOverflowClip(overflowClip.release());
+    object.getMutableForPainting().ensureObjectPaintProperties().setOverflowClip(overflowClip.release());
 }
 
 static FloatPoint perspectiveOrigin(const LayoutBox& box)
 {
     const ComputedStyle& style = box.styleRef();
     FloatSize borderBoxSize(box.size());
     return FloatPoint(
         floatValueForLength(style.perspectiveOriginX(), borderBoxSize.width()),
         floatValueForLength(style.perspectiveOriginY(), borderBoxSize.height()));
 }
 
-void PaintPropertyTreeBuilder::updatePerspective(LayoutObject& object, PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::updatePerspective(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
     const ComputedStyle& style = object.styleRef();
     if (!object.isBox() || !style.hasPerspective())
         return;
 
     RefPtr<TransformPaintPropertyNode> perspective = TransformPaintPropertyNode::create(
         TransformationMatrix().applyPerspective(style.perspective()),
         perspectiveOrigin(toLayoutBox(object)) + toLayoutSize(context.paintOffset),
         context.currentTransform);
     context.currentTransform = perspective.get();
-    object.ensureObjectPaintProperties().setPerspective(perspective.release());
+    object.getMutableForPainting().ensureObjectPaintProperties().setPerspective(perspective.release());
 }
 
-void PaintPropertyTreeBuilder::updateSvgLocalTransform(LayoutObject& object, PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::updateSvgLocalTransform(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
     if (!object.isSVG())
         return;
 
     const AffineTransform& transform = object.localToSVGParentTransform();
     if (transform.isIdentity())
         return;
 
     // The origin is included in the local transform, so use an empty origin.
     RefPtr<TransformPaintPropertyNode> svgLocalTransform = TransformPaintPropertyNode::create(
         transform, FloatPoint3D(0, 0, 0), context.currentTransform);
     context.currentTransform = svgLocalTransform.get();
-    object.ensureObjectPaintProperties().setSvgLocalTransform(svgLocalTransform.release());
+    object.getMutableForPainting().ensureObjectPaintProperties().setSvgLocalTransform(svgLocalTransform.release());
 }
 
-void PaintPropertyTreeBuilder::updateScrollTranslation(LayoutObject& object, PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::updateScrollTranslation(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
     if (!object.isBoxModelObject() || !object.hasOverflowClip())
         return;
 
     PaintLayer* layer = toLayoutBoxModelObject(object).layer();
     ASSERT(layer);
     DoubleSize scrollOffset = layer->getScrollableArea()->scrollOffset();
     if (scrollOffset.isZero() && !layer->scrollsOverflow())
         return;
 
     RefPtr<TransformPaintPropertyNode> scrollTranslation = TransformPaintPropertyNode::create(
         TransformationMatrix().translate(-scrollOffset.width(), -scrollOffset.height()),
         FloatPoint3D(),
         context.currentTransform);
     context.currentTransform = scrollTranslation.get();
-    object.ensureObjectPaintProperties().setScrollTranslation(scrollTranslation.release());
+    object.getMutableForPainting().ensureObjectPaintProperties().setScrollTranslation(scrollTranslation.release());
 }
 
-void PaintPropertyTreeBuilder::updateOutOfFlowContext(LayoutObject& object, PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::updateOutOfFlowContext(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
     if (object.canContainAbsolutePositionObjects()) {
         context.transformForAbsolutePosition = context.currentTransform;
         context.paintOffsetForAbsolutePosition = context.paintOffset;
         context.clipForAbsolutePosition = context.currentClip;
         context.containerForAbsolutePosition = &object;
     }
 
     // TODO(pdr): Remove the !object.isLayoutView() condition when removing FrameView
     // paint properties for rootLayerScrolls.
@@ skipping 14 matching lines @@
         if (context.clipForFixedPosition == cssClip->parent()) {
             context.clipForFixedPosition = cssClip;
             return;
         }
 
         RefPtr<ClipPaintPropertyNode> clipFixedPosition = ClipPaintPropertyNode::create(
             const_cast<TransformPaintPropertyNode*>(cssClip->localTransformSpace()),
             cssClip->clipRect(),
             context.clipForFixedPosition);
         context.clipForFixedPosition = clipFixedPosition.get();
-        object.ensureObjectPaintProperties().setCssClipFixedPosition(clipFixedPosition.release());
+        object.getMutableForPainting().ensureObjectPaintProperties().setCssClipFixedPosition(clipFixedPosition.release());
     }
 }
 
 static void deriveBorderBoxFromContainerContext(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
     if (!object.isBoxModelObject())
         return;
 
     const LayoutBoxModelObject& boxModelObject = toLayoutBoxModelObject(object);
 
     switch (object.styleRef().position()) {
     case StaticPosition:
         break;
     case RelativePosition:
         context.paintOffset += boxModelObject.offsetForInFlowPosition();
         break;
     case AbsolutePosition: {
         context.currentTransform = context.transformForAbsolutePosition;
         context.paintOffset = context.paintOffsetForAbsolutePosition;
 
         // Absolutely positioned content in an inline should be positioned relative to the inline.
-        LayoutObject* container = context.containerForAbsolutePosition;
+        const LayoutObject* container = context.containerForAbsolutePosition;
         if (container && container->isInFlowPositioned() && container->isLayoutInline()) {
             DCHECK(object.isBox());
             context.paintOffset += toLayoutInline(container)->offsetForInFlowPositionedInline(toLayoutBox(object));
         }
 
         context.currentClip = context.clipForAbsolutePosition;
         break;
     }
     case StickyPosition:
         context.paintOffset += boxModelObject.offsetForInFlowPosition();
@@ skipping 12 matching lines @@
         // but their location have the row's location baked-in.
         // Similar adjustment is done in LayoutTableCell::offsetFromContainer().
         if (boxModelObject.isTableCell()) {
             LayoutObject* parentRow = boxModelObject.parent();
             ASSERT(parentRow && parentRow->isTableRow());
             context.paintOffset -= toLayoutBox(parentRow)->locationOffset();
         }
     }
 }
 
-void PaintPropertyTreeBuilder::walk(LayoutObject& object, const PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::buildTreeNodes(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
-    PaintPropertyTreeBuilderContext localContext(context);
-    object.clearObjectPaintProperties();
+    object.getMutableForPainting().clearObjectPaintProperties();
 
-    deriveBorderBoxFromContainerContext(object, localContext);
+    deriveBorderBoxFromContainerContext(object, context);
 
-    updatePaintOffsetTranslation(object, localContext);
-    updateTransform(object, localContext);
-    updateEffect(object, localContext);
-    updateCssClip(object, localContext);
-    updateLocalBorderBoxContext(object, localContext);
-    updateScrollbarPaintOffset(object, localContext);
-    updateOverflowClip(object, localContext);
+    updatePaintOffsetTranslation(object, context);
+    updateTransform(object, context);
+    updateEffect(object, context);
+    updateCssClip(object, context);
+    updateLocalBorderBoxContext(object, context);
+    updateScrollbarPaintOffset(object, context);
+    updateOverflowClip(object, context);
     // TODO(trchen): Insert flattening transform here, as specified by
     // http://www.w3.org/TR/css3-transforms/#transform-style-property
-    updatePerspective(object, localContext);
-    updateSvgLocalTransform(object, localContext);
-    updateScrollTranslation(object, localContext);
-    updateOutOfFlowContext(object, localContext);
-
-    for (LayoutObject* child = object.slowFirstChild(); child; child = child->nextSibling()) {
-        if (child->isBoxModelObject() || child->isSVG())
-            walk(*child, localContext);
-    }
-
-    if (object.isLayoutPart()) {
-        Widget* widget = toLayoutPart(object).widget();
-        if (widget && widget->isFrameView())
-            walk(*toFrameView(widget), localContext);
-        // TODO(pdr): Investigate RemoteFrameView (crbug.com/579281).
-    }
+    updatePerspective(object, context);
+    updateSvgLocalTransform(object, context);
+    updateScrollTranslation(object, context);
+    updateOutOfFlowContext(object, context);
 }
 
 } // namespace blink