[SPv2] Associate effect property nodes for SVG paint chunks

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/LayoutView.h"
 #include "core/layout/svg/LayoutSVGRoot.h"
+#include "core/layout/svg/SVGLayoutSupport.h"
 #include "core/paint/FindPropertiesNeedingUpdate.h"
 #include "core/paint/ObjectPaintProperties.h"
 #include "core/paint/PaintLayer.h"
 #include "core/paint/SVGRootPainter.h"
 #include "platform/transforms/TransformationMatrix.h"
 #include "wtf/PtrUtil.h"
 #include <memory>
 
 namespace blink {
 
@@ skipping 338 matching lines @@
       context.current.shouldFlattenInheritedTransform = true;
     }
   }
 }
 
 void PaintPropertyTreeBuilder::updateEffect(
     const LayoutObject& object,
     PaintPropertyTreeBuilderContext& context) {
   const ComputedStyle& style = object.styleRef();
 
-  // TODO(crbug.com/673500): style.isStackingContext() is only meaningful for
-  // HTML elements. What we really want to ask is whether the element starts
-  // an isolated group, and SVGs use a different rule.
-  if (!style.isStackingContext()) {
+  const bool isIsolatedGroup =
+      (object.isSVG() && !object.isSVGRoot())
+          ? SVGLayoutSupport::willIsolateBlendingDescendantsForObject(&object)
+          : (object.isBoxModelObject() && style.isStackingContext());
+  const bool isSVGGraphicsElement =

[chrishtr, 2016/12/15 19:21:23]

Why skip SVG graphics elements?

[trchen, 2016/12/15 23:49:46]

It is to include SVG graphics elements.
SVGLayoutSupport::willIsolateBlendingDescendantsForObject() exclude them because
they can't have descendants.

But anyhow, I found this condition is still not quite right. The new patchset
fixed existing tests. (Hope it now matches the existing behavior... It does not
100% adhere to the spec and I have to reverse engineer it.)

+      object.isSVGShape() || object.isSVGImage() || object.isSVGText();
+  if (!isIsolatedGroup && !isSVGGraphicsElement) {
     if (object.needsPaintPropertyUpdate() || context.forceSubtreeUpdate) {
       if (auto* properties = object.getMutableForPainting().paintProperties())
         context.forceSubtreeUpdate |= properties->clearEffect();
     }
     return;
   }
 
   // TODO(trchen): Can't omit effect node if we have 3D children.
   if (object.needsPaintPropertyUpdate() || context.forceSubtreeUpdate) {
     bool effectNodeNeeded = false;
@@ skipping 543 matching lines @@
 #endif
 
   updateOverflowClip(object, context);
   updatePerspective(object, context);
   updateSvgLocalToBorderBoxTransform(object, context);
   updateScrollAndScrollTranslation(object, context);
   updateOutOfFlowContext(object, context);
 }
 
 }  // namespace blink