1 files changed, 166 insertions, 119 deletions

diff --git a/Source/WebCore/rendering/svg/SVGRenderSupport.cpp b/Source/WebCore/rendering/svg/SVGRenderSupport.cpp
index 9602927f2..0113c7015 100644
--- a/Source/WebCore/rendering/svg/SVGRenderSupport.cpp
+++ b/Source/WebCore/rendering/svg/SVGRenderSupport.cpp
@@ -23,21 +23,22 @@
  */
 
 #include "config.h"
-
-#if ENABLE(SVG)
 #include "SVGRenderSupport.h"
 
 #include "NodeRenderStyle.h"
+#include "RenderChildIterator.h"
 #include "RenderElement.h"
 #include "RenderGeometryMap.h"
 #include "RenderIterator.h"
 #include "RenderLayer.h"
+#include "RenderSVGImage.h"
 #include "RenderSVGResourceClipper.h"
 #include "RenderSVGResourceFilter.h"
 #include "RenderSVGResourceMarker.h"
 #include "RenderSVGResourceMasker.h"
 #include "RenderSVGRoot.h"
 #include "RenderSVGText.h"
+#include "RenderSVGTransformableContainer.h"
 #include "RenderSVGViewportContainer.h"
 #include "SVGResources.h"
 #include "SVGResourcesCache.h"
@@ -49,8 +50,8 @@ FloatRect SVGRenderSupport::repaintRectForRendererInLocalCoordinatesExcludingSVG
 {
     // FIXME: Add support for RenderSVGBlock.
 
-    if (renderer.isSVGShape() || renderer.isSVGImage() || renderer.isSVGContainer())
-        return toRenderSVGModelObject(renderer).repaintRectInLocalCoordinatesExcludingSVGShadow();
+    if (is<RenderSVGModelObject>(renderer))
+        return downcast<RenderSVGModelObject>(renderer).repaintRectInLocalCoordinatesExcludingSVGShadow();
 
     return renderer.repaintRectInLocalCoordinates();
 }
@@ -67,34 +68,43 @@ LayoutRect SVGRenderSupport::clippedOverflowRectForRepaint(const RenderElement&
     const SVGRenderStyle& svgStyle = renderer.style().svgStyle();
     if (const ShadowData* shadow = svgStyle.shadow())
         shadow->adjustRectForShadow(repaintRect);
-    renderer.computeFloatRectForRepaint(repaintContainer, repaintRect);
-    return enclosingLayoutRect(repaintRect);
+    return enclosingLayoutRect(renderer.computeFloatRectForRepaint(repaintRect, repaintContainer));
 }
 
-void SVGRenderSupport::computeFloatRectForRepaint(const RenderElement& renderer, const RenderLayerModelObject* repaintContainer, FloatRect& repaintRect, bool fixed)
+FloatRect SVGRenderSupport::computeFloatRectForRepaint(const RenderElement& renderer, const FloatRect& repaintRect, const RenderLayerModelObject* repaintContainer, bool fixed)
 {
+    FloatRect adjustedRect = repaintRect;
     const SVGRenderStyle& svgStyle = renderer.style().svgStyle();
     if (const ShadowData* shadow = svgStyle.shadow())
-        shadow->adjustRectForShadow(repaintRect);
-    repaintRect.inflate(renderer.style().outlineWidth());
+        shadow->adjustRectForShadow(adjustedRect);
+    adjustedRect.inflate(renderer.style().outlineWidth());
 
     // Translate to coords in our parent renderer, and then call computeFloatRectForRepaint() on our parent.
-    repaintRect = renderer.localToParentTransform().mapRect(repaintRect);
-    renderer.parent()->computeFloatRectForRepaint(repaintContainer, repaintRect, fixed);
+    adjustedRect = renderer.localToParentTransform().mapRect(adjustedRect);
+    return renderer.parent()->computeFloatRectForRepaint(adjustedRect, repaintContainer, fixed);
 }
 
-void SVGRenderSupport::mapLocalToContainer(const RenderElement& renderer, const RenderLayerModelObject* repaintContainer, TransformState& transformState, bool* wasFixed)
+const RenderElement& SVGRenderSupport::localToParentTransform(const RenderElement& renderer, AffineTransform &transform)
 {
-    transformState.applyTransform(renderer.localToParentTransform());
-
     ASSERT(renderer.parent());
     auto& parent = *renderer.parent();
-    
-    // At the SVG/HTML boundary (aka RenderSVGRoot), we apply the localToBorderBoxTransform 
+
+    // At the SVG/HTML boundary (aka RenderSVGRoot), we apply the localToBorderBoxTransform
     // to map an element from SVG viewport coordinates to CSS box coordinates.
-    // RenderSVGRoot's mapLocalToContainer method expects CSS box coordinates.
-    if (parent.isSVGRoot())
-        transformState.applyTransform(toRenderSVGRoot(parent).localToBorderBoxTransform());
+    if (is<RenderSVGRoot>(parent))
+        transform = downcast<RenderSVGRoot>(parent).localToBorderBoxTransform() * renderer.localToParentTransform();
+    else
+        transform = renderer.localToParentTransform();
+
+    return parent;
+}
+
+void SVGRenderSupport::mapLocalToContainer(const RenderElement& renderer, const RenderLayerModelObject* repaintContainer, TransformState& transformState, bool* wasFixed)
+{
+    AffineTransform transform;
+    auto& parent = localToParentTransform(renderer, transform);
+
+    transformState.applyTransform(transform);
 
     MapCoordinatesFlags mode = UseTransforms;
     parent.mapLocalToContainer(repaintContainer, transformState, mode, wasFixed);
@@ -104,19 +114,10 @@ const RenderElement* SVGRenderSupport::pushMappingToContainer(const RenderElemen
 {
     ASSERT_UNUSED(ancestorToStopAt, ancestorToStopAt != &renderer);
 
-    ASSERT(renderer.parent());
-    auto& parent = *renderer.parent();
-
-    // At the SVG/HTML boundary (aka RenderSVGRoot), we apply the localToBorderBoxTransform 
-    // to map an element from SVG viewport coordinates to CSS box coordinates.
-    // RenderSVGRoot's mapLocalToContainer method expects CSS box coordinates.
-    if (parent.isSVGRoot()) {
-        TransformationMatrix matrix(renderer.localToParentTransform());
-        matrix.multiply(toRenderSVGRoot(parent).localToBorderBoxTransform());
-        geometryMap.push(&renderer, matrix);
-    } else
-        geometryMap.push(&renderer, renderer.localToParentTransform());
+    AffineTransform transform;
+    auto& parent = localToParentTransform(renderer, transform);
 
+    geometryMap.push(&renderer, transform);
     return &parent;
 }
 
@@ -127,13 +128,13 @@ bool SVGRenderSupport::checkForSVGRepaintDuringLayout(const RenderElement& rende
     // When a parent container is transformed in SVG, all children will be painted automatically
     // so we are able to skip redundant repaint checks.
     auto parent = renderer.parent();
-    return !(parent && parent->isSVGContainer() && toRenderSVGContainer(parent)->didTransformToRootUpdate());
+    return !(is<RenderSVGContainer>(parent) && downcast<RenderSVGContainer>(*parent).didTransformToRootUpdate());
 }
 
 // Update a bounding box taking into account the validity of the other bounding box.
-static inline void updateObjectBoundingBox(FloatRect& objectBoundingBox, bool& objectBoundingBoxValid, RenderObject* other, FloatRect otherBoundingBox)
+static inline void updateObjectBoundingBox(FloatRect& objectBoundingBox, bool& objectBoundingBoxValid, const RenderObject* other, FloatRect otherBoundingBox)
 {
-    bool otherValid = other->isSVGContainer() ? toRenderSVGContainer(other)->isObjectBoundingBoxValid() : true;
+    bool otherValid = is<RenderSVGContainer>(*other) ? downcast<RenderSVGContainer>(*other).isObjectBoundingBoxValid() : true;
     if (!otherValid)
         return;
 
@@ -155,17 +156,21 @@ void SVGRenderSupport::computeContainerBoundingBoxes(const RenderElement& contai
     // When computing the strokeBoundingBox, we use the repaintRects of the container's children so that the container's stroke includes
     // the resources applied to the children (such as clips and filters). This allows filters applied to containers to correctly bound
     // the children, and also improves inlining of SVG content, as the stroke bound is used in that situation also.
-    for (RenderObject* current = container.firstChild(); current; current = current->nextSibling()) {
-        if (current->isSVGHiddenContainer())
+    for (auto& current : childrenOfType<RenderObject>(container)) {
+        if (current.isSVGHiddenContainer())
+            continue;
+
+        // Don't include elements in the union that do not render.
+        if (is<RenderSVGShape>(current) && downcast<RenderSVGShape>(current).isRenderingDisabled())
             continue;
 
-        const AffineTransform& transform = current->localToParentTransform();
+        const AffineTransform& transform = current.localToParentTransform();
         if (transform.isIdentity()) {
-            updateObjectBoundingBox(objectBoundingBox, objectBoundingBoxValid, current, current->objectBoundingBox());
-            strokeBoundingBox.unite(current->repaintRectInLocalCoordinates());
+            updateObjectBoundingBox(objectBoundingBox, objectBoundingBoxValid, &current, current.objectBoundingBox());
+            strokeBoundingBox.unite(current.repaintRectInLocalCoordinates());
         } else {
-            updateObjectBoundingBox(objectBoundingBox, objectBoundingBoxValid, current, transform.mapRect(current->objectBoundingBox()));
-            strokeBoundingBox.unite(transform.mapRect(current->repaintRectInLocalCoordinates()));
+            updateObjectBoundingBox(objectBoundingBox, objectBoundingBoxValid, &current, transform.mapRect(current.objectBoundingBox()));
+            strokeBoundingBox.unite(transform.mapRect(current.repaintRectInLocalCoordinates()));
         }
     }
 
@@ -180,141 +185,149 @@ bool SVGRenderSupport::paintInfoIntersectsRepaintRect(const FloatRect& localRepa
     return localTransform.mapRect(localRepaintRect).intersects(paintInfo.rect);
 }
 
-const RenderSVGRoot& SVGRenderSupport::findTreeRootObject(const RenderElement& start)
+RenderSVGRoot* SVGRenderSupport::findTreeRootObject(RenderElement& start)
 {
-    return *lineageOfType<RenderSVGRoot>(start).first();
+    return lineageOfType<RenderSVGRoot>(start).first();
 }
 
-static inline void invalidateResourcesOfChildren(RenderObject& start)
+const RenderSVGRoot* SVGRenderSupport::findTreeRootObject(const RenderElement& start)
 {
-    ASSERT(!start.needsLayout());
-    if (SVGResources* resources = SVGResourcesCache::cachedResourcesForRenderObject(start))
-        resources->removeClientFromCache(start, false);
+    return lineageOfType<RenderSVGRoot>(start).first();
+}
+
+static inline void invalidateResourcesOfChildren(RenderElement& renderer)
+{
+    ASSERT(!renderer.needsLayout());
+    if (auto* resources = SVGResourcesCache::cachedResourcesForRenderer(renderer))
+        resources->removeClientFromCache(renderer, false);
 
-    for (RenderObject* child = start.firstChildSlow(); child; child = child->nextSibling())
-        invalidateResourcesOfChildren(*child);
+    for (auto& child : childrenOfType<RenderElement>(renderer))
+        invalidateResourcesOfChildren(child);
 }
 
 static inline bool layoutSizeOfNearestViewportChanged(const RenderElement& renderer)
 {
     const RenderElement* start = &renderer;
-    while (start && !start->isSVGRoot() && !start->isSVGViewportContainer())
+    while (start && !is<RenderSVGRoot>(*start) && !is<RenderSVGViewportContainer>(*start))
         start = start->parent();
 
     ASSERT(start);
-    ASSERT(start->isSVGRoot() || start->isSVGViewportContainer());
-    if (start->isSVGViewportContainer())
-        return toRenderSVGViewportContainer(start)->isLayoutSizeChanged();
+    if (is<RenderSVGViewportContainer>(*start))
+        return downcast<RenderSVGViewportContainer>(*start).isLayoutSizeChanged();
 
-    return toRenderSVGRoot(start)->isLayoutSizeChanged();
+    return downcast<RenderSVGRoot>(*start).isLayoutSizeChanged();
 }
 
 bool SVGRenderSupport::transformToRootChanged(RenderElement* ancestor)
 {
-    while (ancestor && !ancestor->isSVGRoot()) {
-        if (ancestor->isSVGTransformableContainer())
-            return toRenderSVGContainer(ancestor)->didTransformToRootUpdate();
-        if (ancestor->isSVGViewportContainer())
-            return toRenderSVGViewportContainer(ancestor)->didTransformToRootUpdate();
+    while (ancestor && !is<RenderSVGRoot>(*ancestor)) {
+        if (is<RenderSVGTransformableContainer>(*ancestor))
+            return downcast<RenderSVGTransformableContainer>(*ancestor).didTransformToRootUpdate();
+        if (is<RenderSVGViewportContainer>(*ancestor))
+            return downcast<RenderSVGViewportContainer>(*ancestor).didTransformToRootUpdate();
         ancestor = ancestor->parent();
     }
 
     return false;
 }
 
+void SVGRenderSupport::layoutDifferentRootIfNeeded(const RenderElement& renderer)
+{
+    if (auto* resources = SVGResourcesCache::cachedResourcesForRenderer(renderer)) {
+        auto* svgRoot = SVGRenderSupport::findTreeRootObject(renderer);
+        ASSERT(svgRoot);
+        resources->layoutDifferentRootIfNeeded(svgRoot);
+    }
+}
+
 void SVGRenderSupport::layoutChildren(RenderElement& start, bool selfNeedsLayout)
 {
     bool layoutSizeChanged = layoutSizeOfNearestViewportChanged(start);
     bool transformChanged = transformToRootChanged(&start);
     bool hasSVGShadow = rendererHasSVGShadow(start);
     bool needsBoundariesUpdate = start.needsBoundariesUpdate();
-    HashSet<RenderObject*> notlayoutedObjects;
+    HashSet<RenderElement*> elementsThatDidNotReceiveLayout;
 
-    for (RenderObject* child = start.firstChild(); child; child = child->nextSibling()) {
+    for (auto& child : childrenOfType<RenderObject>(start)) {
         bool needsLayout = selfNeedsLayout;
-        bool childEverHadLayout = child->everHadLayout();
+        bool childEverHadLayout = child.everHadLayout();
 
         if (needsBoundariesUpdate && hasSVGShadow) {
             // If we have a shadow, our shadow is baked into our children's cached boundaries,
             // so they need to update.
-            child->setNeedsBoundariesUpdate();
+            child.setNeedsBoundariesUpdate();
             needsLayout = true;
         }
 
         if (transformChanged) {
             // If the transform changed we need to update the text metrics (note: this also happens for layoutSizeChanged=true).
-            if (child->isSVGText())
-                toRenderSVGText(child)->setNeedsTextMetricsUpdate();
+            if (is<RenderSVGText>(child))
+                downcast<RenderSVGText>(child).setNeedsTextMetricsUpdate();
             needsLayout = true;
         }
 
-        if (layoutSizeChanged) {
+        if (layoutSizeChanged && is<SVGElement>(*child.node())) {
             // When selfNeedsLayout is false and the layout size changed, we have to check whether this child uses relative lengths
-            if (SVGElement* element = child->node()->isSVGElement() ? toSVGElement(child->node()) : 0) {
-                if (element->hasRelativeLengths()) {
-                    // When the layout size changed and when using relative values tell the RenderSVGShape to update its shape object
-                    if (child->isSVGShape())
-                        toRenderSVGShape(child)->setNeedsShapeUpdate();
-                    else if (child->isSVGText()) {
-                        toRenderSVGText(child)->setNeedsTextMetricsUpdate();
-                        toRenderSVGText(child)->setNeedsPositioningValuesUpdate();
-                    }
-
-                    needsLayout = true;
+            auto& element = downcast<SVGElement>(*child.node());
+            if (element.hasRelativeLengths()) {
+                // When the layout size changed and when using relative values tell the RenderSVGShape to update its shape object
+                if (is<RenderSVGShape>(child))
+                    downcast<RenderSVGShape>(child).setNeedsShapeUpdate();
+                else if (is<RenderSVGText>(child)) {
+                    auto& svgText = downcast<RenderSVGText>(child);
+                    svgText.setNeedsTextMetricsUpdate();
+                    svgText.setNeedsPositioningValuesUpdate();
                 }
+
+                needsLayout = true;
             }
         }
 
         if (needsLayout)
-            child->setNeedsLayout(MarkOnlyThis);
+            child.setNeedsLayout(MarkOnlyThis);
 
-        if (child->needsLayout()) {
-            toRenderElement(child)->layout();
+        if (child.needsLayout()) {
+            layoutDifferentRootIfNeeded(downcast<RenderElement>(child));
+            downcast<RenderElement>(child).layout();
             // Renderers are responsible for repainting themselves when changing, except
             // for the initial paint to avoid potential double-painting caused by non-sensical "old" bounds.
             // We could handle this in the individual objects, but for now it's easier to have
             // parent containers call repaint().  (RenderBlock::layout* has similar logic.)
             if (!childEverHadLayout)
-                child->repaint();
-        } else if (layoutSizeChanged)
-            notlayoutedObjects.add(child);
+                child.repaint();
+        } else if (layoutSizeChanged && is<RenderElement>(child))
+            elementsThatDidNotReceiveLayout.add(&downcast<RenderElement>(child));
 
-        ASSERT(!child->needsLayout());
+        ASSERT(!child.needsLayout());
     }
 
     if (!layoutSizeChanged) {
-        ASSERT(notlayoutedObjects.isEmpty());
+        ASSERT(elementsThatDidNotReceiveLayout.isEmpty());
         return;
     }
 
     // If the layout size changed, invalidate all resources of all children that didn't go through the layout() code path.
-    for (auto child : notlayoutedObjects)
-        invalidateResourcesOfChildren(*child);
+    for (auto* element : elementsThatDidNotReceiveLayout)
+        invalidateResourcesOfChildren(*element);
 }
 
 bool SVGRenderSupport::isOverflowHidden(const RenderElement& renderer)
 {
-    // SVG doesn't support independent x/y overflow
-    ASSERT(renderer.style().overflowX() == renderer.style().overflowY());
-
-    // OSCROLL is never set for SVG - see StyleResolver::adjustRenderStyle
-    ASSERT(renderer.style().overflowX() != OSCROLL);
-
     // RenderSVGRoot should never query for overflow state - it should always clip itself to the initial viewport size.
-    ASSERT(!renderer.isRoot());
+    ASSERT(!renderer.isDocumentElementRenderer());
 
-    return renderer.style().overflowX() == OHIDDEN;
+    return renderer.style().overflowX() == OHIDDEN || renderer.style().overflowX() == OSCROLL;
 }
 
 bool SVGRenderSupport::rendererHasSVGShadow(const RenderObject& renderer)
 {
     // FIXME: Add support for RenderSVGBlock.
 
-    if (renderer.isSVGShape() || renderer.isSVGImage() || renderer.isSVGContainer())
-        return toRenderSVGModelObject(renderer).hasSVGShadow();
+    if (is<RenderSVGModelObject>(renderer))
+        return downcast<RenderSVGModelObject>(renderer).hasSVGShadow();
 
-    if (renderer.isSVGRoot())
-        return toRenderSVGRoot(renderer).hasSVGShadow();
+    if (is<RenderSVGRoot>(renderer))
+        return downcast<RenderSVGRoot>(renderer).hasSVGShadow();
 
     return false;
 }
@@ -323,13 +336,13 @@ void SVGRenderSupport::setRendererHasSVGShadow(RenderObject& renderer, bool hasS
 {
     // FIXME: Add support for RenderSVGBlock.
 
-    if (renderer.isSVGShape() || renderer.isSVGImage() || renderer.isSVGContainer()) {
-        toRenderSVGModelObject(renderer).setHasSVGShadow(hasShadow);
+    if (is<RenderSVGModelObject>(renderer)) {
+        downcast<RenderSVGModelObject>(renderer).setHasSVGShadow(hasShadow);
         return;
     }
 
-    if (renderer.isSVGRoot())
-        toRenderSVGRoot(renderer).setHasSVGShadow(hasShadow);
+    if (is<RenderSVGRoot>(renderer))
+        downcast<RenderSVGRoot>(renderer).setHasSVGShadow(hasShadow);
 }
 
 void SVGRenderSupport::intersectRepaintRectWithShadows(const RenderElement& renderer, FloatRect& repaintRect)
@@ -357,20 +370,18 @@ void SVGRenderSupport::intersectRepaintRectWithShadows(const RenderElement& rend
     if (localToRootTransform.isIdentity())
         return;
 
-    AffineTransform rootToLocalTransform = localToRootTransform.inverse();
+    AffineTransform rootToLocalTransform = localToRootTransform.inverse().value_or(AffineTransform());
     repaintRect = rootToLocalTransform.mapRect(repaintRect);
 }
 
 void SVGRenderSupport::intersectRepaintRectWithResources(const RenderElement& renderer, FloatRect& repaintRect)
 {
-    SVGResources* resources = SVGResourcesCache::cachedResourcesForRenderObject(renderer);
+    auto* resources = SVGResourcesCache::cachedResourcesForRenderer(renderer);
     if (!resources)
         return;
 
-#if ENABLE(FILTERS)
     if (RenderSVGResourceFilter* filter = resources->filter())
         repaintRect = filter->resourceBoundingBox(renderer);
-#endif
 
     if (RenderSVGResourceClipper* clipper = resources->clipper())
         repaintRect.intersect(clipper->resourceBoundingBox(renderer));
@@ -386,7 +397,7 @@ bool SVGRenderSupport::filtersForceContainerLayout(const RenderElement& renderer
     if (!renderer.normalChildNeedsLayout())
         return false;
 
-    SVGResources* resources = SVGResourcesCache::cachedResourcesForRenderObject(renderer);
+    auto* resources = SVGResourcesCache::cachedResourcesForRenderer(renderer);
     if (!resources || !resources->filter())
         return false;
 
@@ -397,7 +408,7 @@ bool SVGRenderSupport::pointInClippingArea(const RenderElement& renderer, const
 {
     // We just take clippers into account to determine if a point is on the node. The Specification may
     // change later and we also need to check maskers.
-    SVGResources* resources = SVGResourcesCache::cachedResourcesForRenderObject(renderer);
+    auto* resources = SVGResourcesCache::cachedResourcesForRenderer(renderer);
     if (!resources)
         return true;
 
@@ -415,23 +426,31 @@ void SVGRenderSupport::applyStrokeStyleToContext(GraphicsContext* context, const
 
     const SVGRenderStyle& svgStyle = style.svgStyle();
 
-    SVGLengthContext lengthContext(toSVGElement(renderer.element()));
-    context->setStrokeThickness(svgStyle.strokeWidth().value(lengthContext));
-    context->setLineCap(svgStyle.capStyle());
-    context->setLineJoin(svgStyle.joinStyle());
-    if (svgStyle.joinStyle() == MiterJoin)
+    SVGLengthContext lengthContext(downcast<SVGElement>(renderer.element()));
+    context->setStrokeThickness(lengthContext.valueForLength(style.strokeWidth()));
+    context->setLineCap(style.capStyle());
+    context->setLineJoin(style.joinStyle());
+    if (style.joinStyle() == MiterJoin)
         context->setMiterLimit(svgStyle.strokeMiterLimit());
 
-    const Vector<SVGLength>& dashes = svgStyle.strokeDashArray();
+    const Vector<SVGLengthValue>& dashes = svgStyle.strokeDashArray();
     if (dashes.isEmpty())
         context->setStrokeStyle(SolidStroke);
     else {
         DashArray dashArray;
         dashArray.reserveInitialCapacity(dashes.size());
-        for (unsigned i = 0, size = dashes.size(); i < size; ++i)
-            dashArray.uncheckedAppend(dashes[i].value(lengthContext));
+        bool canSetLineDash = false;
 
-        context->setLineDash(dashArray, svgStyle.strokeDashOffset().value(lengthContext));
+        for (auto& dash : dashes) {
+            dashArray.uncheckedAppend(dash.value(lengthContext));
+            if (dashArray.last() > 0)
+                canSetLineDash = true;
+        }
+
+        if (canSetLineDash)
+            context->setLineDash(dashArray, lengthContext.valueForLength(svgStyle.strokeDashOffset()));
+        else
+            context->setStrokeStyle(SolidStroke);
     }
 }
 
@@ -440,12 +459,40 @@ void SVGRenderSupport::childAdded(RenderElement& parent, RenderObject& child)
     SVGRenderSupport::setRendererHasSVGShadow(child, SVGRenderSupport::rendererHasSVGShadow(parent) || SVGRenderSupport::rendererHasSVGShadow(child));
 }
 
-void SVGRenderSupport::styleChanged(RenderElement& renderer)
+void SVGRenderSupport::styleChanged(RenderElement& renderer, const RenderStyle* oldStyle)
 {
     auto parent = renderer.parent();
     SVGRenderSupport::setRendererHasSVGShadow(renderer, (parent && SVGRenderSupport::rendererHasSVGShadow(*parent)) || renderer.style().svgStyle().shadow());
+
+#if ENABLE(CSS_COMPOSITING)
+    if (renderer.element() && renderer.element()->isSVGElement() && (!oldStyle || renderer.style().hasBlendMode() != oldStyle->hasBlendMode()))
+        SVGRenderSupport::updateMaskedAncestorShouldIsolateBlending(renderer);
+#else
+    UNUSED_PARAM(oldStyle);
+#endif
 }
 
+#if ENABLE(CSS_COMPOSITING)
+bool SVGRenderSupport::isolatesBlending(const RenderStyle& style)
+{
+    return style.svgStyle().isolatesBlending() || style.hasFilter() || style.hasBlendMode() || style.opacity() < 1.0f;
 }
 
+void SVGRenderSupport::updateMaskedAncestorShouldIsolateBlending(const RenderElement& renderer)
+{
+    ASSERT(renderer.element());
+    ASSERT(renderer.element()->isSVGElement());
+
+    bool maskedAncestorShouldIsolateBlending = renderer.style().hasBlendMode();
+    for (auto* ancestor = renderer.element()->parentElement(); ancestor && ancestor->isSVGElement(); ancestor = ancestor->parentElement()) {
+        if (!downcast<SVGElement>(*ancestor).isSVGGraphicsElement() || !isolatesBlending(*ancestor->computedStyle()))
+            continue;
+
+        if (ancestor->computedStyle()->svgStyle().hasMasker())
+            downcast<SVGGraphicsElement>(*ancestor).setShouldIsolateBlending(maskedAncestorShouldIsolateBlending);
+
+        return;
+    }
+}
 #endif
+}