Switch the RootLayerScrolls codepath to use root effect paint properties

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"
@@ skipping 33 matching lines @@
         DEFINE_STATIC_REF(ScrollPaintPropertyNode, rootScroll, (ScrollPaintPropertyNode::create(nullptr, rootTransformNode(), IntSize(), IntSize(), false, false)));
         return rootScroll;
     }
 }
 
 PaintPropertyTreeBuilderContext PaintPropertyTreeBuilder::setupInitialContext()
 {
     PaintPropertyTreeBuilderContext context;
 
     context.current.clip = context.absolutePosition.clip = context.fixedPosition.clip = rootClipNode();
+    context.currentEffect = rootEffectNode();
 
-    // TODO(pdr): Update the root layer scrolling paths to use the static root nodes for transform, effect, and scroll.
+    // TODO(pdr): Update the root layer scrolling paths to use the static root nodes for transform and scroll.
     if (RuntimeEnabledFeatures::rootLayerScrollingEnabled())
         return context;
 
     context.current.transform = context.absolutePosition.transform = context.fixedPosition.transform = rootTransformNode();
     context.current.scroll = context.absolutePosition.scroll = context.fixedPosition.scroll = rootScrollNode();
-    context.currentEffect = rootEffectNode();
 
     // Ensure scroll tree properties are reset. They will be rebuilt during the tree walk.
     rootScrollNode()->clearMainThreadScrollingReasons();
 
     return context;
 }
 
 void createOrUpdateFrameViewPreTranslation(FrameView& frameView,
     PassRefPtr<const TransformPaintPropertyNode> parent,
     const TransformationMatrix& matrix,
@@ skipping 200 matching lines @@
             return;
         }
     }
 
     if (ObjectPaintProperties* properties = object.getMutableForPainting().objectPaintProperties())
         properties->clearTransform();
 }
 
 void PaintPropertyTreeBuilder::updateEffect(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
-    if (object.isLayoutView() && !context.currentEffect) {
-        const LayoutView& layoutView = toLayoutView(object);
-        DCHECK(RuntimeEnabledFeatures::rootLayerScrollingEnabled());
-        DCHECK(layoutView.frameView()->frame().isMainFrame());
-        context.currentEffect = layoutView.getMutableForPainting().ensureObjectPaintProperties().createOrUpdateEffect(nullptr, 1.0);
-        return;
-    }
-
     if (!object.styleRef().hasOpacity()) {
         if (ObjectPaintProperties* properties = object.getMutableForPainting().objectPaintProperties())
             properties->clearEffect();
         return;
     }
 
     context.currentEffect = object.getMutableForPainting().ensureObjectPaintProperties().createOrUpdateEffect(
         context.currentEffect, object.styleRef().opacity());
 }
 
@@ skipping 290 matching lines @@
         return;
 
     updateOverflowClip(object, context);
     updatePerspective(object, context);
     updateSvgLocalToBorderBoxTransform(object, context);
     updateScrollAndScrollTranslation(object, context);
     updateOutOfFlowContext(object, context);
 }
 
 } // namespace blink