Add static root property tree nodes [spv2]

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/layout/LayoutView.h"
 #include "core/layout/svg/LayoutSVGRoot.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 {
 
-void PaintPropertyTreeBuilder::buildTreeRootNodes(FrameView& rootFrame, PaintPropertyTreeBuilderContext& context)
-{
-    if (RuntimeEnabledFeatures::rootLayerScrollingEnabled())
-        return;
-
-    if (!rootFrame.rootTransform() || rootFrame.rootTransform()->parent()) {
-        rootFrame.setRootTransform(TransformPaintPropertyNode::create(nullptr, TransformationMatrix(), FloatPoint3D()));
-        rootFrame.setRootClip(ClipPaintPropertyNode::create(nullptr, rootFrame.rootTransform(), FloatRoundedRect(LayoutRect::infiniteIntRect())));
-        rootFrame.setRootEffect(EffectPaintPropertyNode::create(nullptr, 1.0));
-        rootFrame.setRootScroll(ScrollPaintPropertyNode::create(nullptr, rootFrame.rootTransform(), IntSize(), IntSize(), false, false));
-    } else {
-        DCHECK(rootFrame.rootClip() && !rootFrame.rootClip()->parent());
-        DCHECK(rootFrame.rootEffect() && !rootFrame.rootEffect()->parent());
-        DCHECK(rootFrame.rootScroll() && !rootFrame.rootScroll()->parent());
-        // Ensure main thread scroll reasons are reset.
-        rootFrame.rootScroll()->update(nullptr, rootFrame.rootTransform(), IntSize(), IntSize(), false, false);
+namespace {
+    TransformPaintPropertyNode* rootTransformNode()
+    {
+        DEFINE_STATIC_REF(TransformPaintPropertyNode, rootTransform, (TransformPaintPropertyNode::create(nullptr, TransformationMatrix(), FloatPoint3D())));
+        return rootTransform;
     }
 
-    context.current.transform = context.absolutePosition.transform = context.fixedPosition.transform = rootFrame.rootTransform();
-    context.current.scroll = rootFrame.rootScroll();
-    context.current.clip = context.absolutePosition.clip = context.fixedPosition.clip = rootFrame.rootClip();
-    context.currentEffect = rootFrame.rootEffect();
+    ClipPaintPropertyNode* rootClipNode()
+    {
+        DEFINE_STATIC_REF(ClipPaintPropertyNode, rootClip, (ClipPaintPropertyNode::create(nullptr, rootTransformNode(), FloatRoundedRect(LayoutRect::infiniteIntRect()))));
+        return rootClip;
+    }
+
+    EffectPaintPropertyNode* rootEffectNode()
+    {
+        DEFINE_STATIC_REF(EffectPaintPropertyNode, rootEffect, (EffectPaintPropertyNode::create(nullptr, 1.0)));
+        return rootEffect;
+    }
+
+    ScrollPaintPropertyNode* rootScrollNode()
+    {
+        DEFINE_STATIC_REF(ScrollPaintPropertyNode, rootScroll, (ScrollPaintPropertyNode::create(nullptr, rootTransformNode(), IntSize(), IntSize(), false, false)));
+        return rootScroll;
+    }
+}
+
+PaintPropertyTreeBuilderContext PaintPropertyTreeBuilder::setupInitialContext()
+{
+    PaintPropertyTreeBuilderContext context;
+
+    // TODO(pdr): Update the root layer scrolling paths to use the static root nodes.
+    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.current.clip = context.absolutePosition.clip = context.fixedPosition.clip = rootClipNode();
+    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,
     const FloatPoint3D& origin)
 {
     DCHECK(!RuntimeEnabledFeatures::rootLayerScrollingEnabled());
     if (TransformPaintPropertyNode* existingPreTranslation = frameView.preTranslation())
         existingPreTranslation->update(std::move(parent), matrix, origin);
@@ skipping 94 matching lines @@
     context.current.paintOffset = LayoutPoint();
     context.current.clip = frameView.contentClip();
     context.current.scroll = frameView.scroll() ? frameView.scroll() : initialScroll;
     context.current.renderingContextID = 0;
     context.current.shouldFlattenInheritedTransform = true;
     context.absolutePosition = context.current;
     context.containerForAbsolutePosition = nullptr;
     context.fixedPosition = context.current;
     context.fixedPosition.transform = frameView.preTranslation();
     context.fixedPosition.scroll = initialScroll;
+
+    std::unique_ptr<PropertyTreeState> contentsState(new PropertyTreeState(context.current.transform, context.current.clip, context.currentEffect, context.current.scroll));
+    frameView.setTotalPropertyTreeStateForContents(std::move(contentsState));
 }
 
 void PaintPropertyTreeBuilder::updatePaintOffsetTranslation(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
     if (object.isBoxModelObject() && context.current.paintOffset != LayoutPoint()) {
         // TODO(trchen): Eliminate PaintLayer dependency.
         PaintLayer* layer = toLayoutBoxModelObject(object).layer();
         if (layer && layer->paintsWithTransform(GlobalPaintNormalPhase)) {
             // We should use the same subpixel paint offset values for snapping regardless of whether a
             // transform is present. If there is a transform we round the paint offset but keep around
@@ skipping 404 matching lines @@
         return;
 
     updateOverflowClip(object, context);
     updatePerspective(object, context);
     updateSvgLocalToBorderBoxTransform(object, context);
     updateScrollAndScrollTranslation(object, context);
     updateOutOfFlowContext(object, context);
 }
 
 } // namespace blink