[SPv2] Add filter support in PaintArtifactCompositor

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/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 {
 
 PaintPropertyTreeBuilderContext
 PaintPropertyTreeBuilder::setupInitialContext() {
   PaintPropertyTreeBuilderContext context;
   context.current.clip = context.absolutePosition.clip =
       context.fixedPosition.clip = ClipPaintPropertyNode::root();
   context.currentEffect = EffectPaintPropertyNode::root();
+  context.inputClipOfCurrentEffect = ClipPaintPropertyNode::root();
   context.current.transform = context.absolutePosition.transform =
       context.fixedPosition.transform = TransformPaintPropertyNode::root();
   context.current.scroll = context.absolutePosition.scroll =
       context.fixedPosition.scroll = ScrollPaintPropertyNode::root();
   return context;
 }
 
 void updateFrameViewPreTranslation(
     FrameView& frameView,
     PassRefPtr<const TransformPaintPropertyNode> parent,
@@ skipping 332 matching lines @@
       effectNodeNeeded = true;
 
     CompositorFilterOperations filter;
     if (object.isSVG() && !object.isSVGRoot()) {
       // TODO(trchen): SVG caches filters in SVGResources. Implement it.
     } else if (PaintLayer* layer = toLayoutBoxModelObject(object).layer()) {
       // TODO(trchen): Eliminate PaintLayer dependency.
       filter = layer->createCompositorFilterOperationsForFilter(style);
     }
 
-    const ClipPaintPropertyNode* outputClip = ClipPaintPropertyNode::root();
+    const ClipPaintPropertyNode* outputClip = context.inputClipOfCurrentEffect;
     // The CSS filter spec didn't specify how filters interact with overflow
     // clips. The implementation here mimics the old Blink/WebKit behavior for
     // backward compatibility.
     // Basically the output of the filter will be affected by clips that applies
     // to the current element. The descendants that paints into the input of the
     // filter ignores any clips collected so far. For example:
     // <div style="overflow:scroll">
     //   <div style="filter:blur(1px);">
     //     <div>A</div>
     //     <div style="position:absolute;">B</div>
@@ skipping 20 matching lines @@
           std::move(filter), opacity);
     } else {
       if (auto* properties = object.getMutableForPainting().paintProperties())
         properties->clearEffect();
     }
   }
 
   const auto* properties = object.paintProperties();
   if (properties && properties->effect()) {
     context.currentEffect = properties->effect();
-    // TODO(pdr): Once the expansion clip node is created above, it should be
-    // used here to update all current clip nodes;
-    const ClipPaintPropertyNode* expansionHint = context.current.clip;
-    context.current.clip = context.absolutePosition.clip =
-        context.fixedPosition.clip = expansionHint;
+    if (!properties->effect()->filter().isEmpty()) {
+      // TODO(trchen): Change input clip to expansion hint created above.

[chrishtr, 2016/11/23 17:40:51]

This comment is now out of date - there is no expansion hint referenced above.

+      const ClipPaintPropertyNode* inputClip =
+          properties->effect()->outputClip();
+      context.inputClipOfCurrentEffect = context.current.clip =
+          context.absolutePosition.clip = context.fixedPosition.clip =
+              inputClip;
+    }
   }
 }
 
 void PaintPropertyTreeBuilder::updateCssClip(
     const LayoutObject& object,
     PaintPropertyTreeBuilderContext& context) {
   if (object.needsPaintPropertyUpdate()) {
     if (object.hasClip()) {
       // Create clip node for descendants that are not fixed position.
       // We don't have to setup context.absolutePosition.clip here because this
@@ skipping 463 matching lines @@
 #endif
 
   updateOverflowClip(object, context);
   updatePerspective(object, context);
   updateSvgLocalToBorderBoxTransform(object, context);
   updateScrollAndScrollTranslation(object, context);
   updateOutOfFlowContext(object, context);
 }
 
 }  // namespace blink