WIP: Construct SPV2's scroll paint property tree

third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.cpp

Index: third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.cpp b/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.cpp
index f57b66166d4eb51fe2e352176ad8449a072603d3..4f81a90069a60b63e3b7dc6c593c59ff9f6155e2 100644
--- a/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilder.cpp
@@ -28,12 +28,14 @@ void PaintPropertyTreeBuilder::buildTreeRootNodes(FrameView& rootFrame, PaintPro
         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(), FloatSize(), FloatSize(), false, false));
     } else {
         DCHECK(rootFrame.rootClip() && !rootFrame.rootClip()->parent());
         DCHECK(rootFrame.rootEffect() && !rootFrame.rootEffect()->parent());
     }
 
     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();
 }
@@ -51,6 +53,8 @@ void PaintPropertyTreeBuilder::buildTreeNodes(FrameView& frameView, PaintPropert
             frameView.y() + layoutView->location().y() + context.current.paintOffset.y());
         context.current.transform = layoutView->getMutableForPainting().ensureObjectPaintProperties().createOrUpdatePaintOffsetTranslation(
             context.current.transform, frameTranslate, FloatPoint3D());
+        context.current.scroll = layoutView->getMutableForPainting().ensureObjectPaintProperties().createOrUpdateScroll(
+            context.current.scroll, context.current.transform, FloatSize(), FloatSize(), false, false);
         context.current.paintOffset = LayoutPoint();
         context.current.renderingContextID = 0;
         context.current.shouldFlattenInheritedTransform = true;
@@ -81,12 +85,23 @@ void PaintPropertyTreeBuilder::buildTreeNodes(FrameView& frameView, PaintPropert
     else
         frameView.setScrollTranslation(TransformPaintPropertyNode::create(frameView.preTranslation(), frameScroll, FloatPoint3D()));
 
+    // TODO(pdr): Set these values properly.
+    FloatSize scrollClip;
+    FloatSize scrollBounds;
+    bool userScrollableHorizontal = false;
+    bool userScrollableVertical = false;
+    if (ScrollPaintPropertyNode* existingScroll = frameView.scroll())
+        existingScroll->update(context.current.scroll, frameView.scrollTranslation(), scrollClip, scrollBounds, userScrollableHorizontal, userScrollableVertical);
+    else
+        frameView.setScroll(ScrollPaintPropertyNode::create(context.current.scroll, frameView.scrollTranslation(), scrollClip, scrollBounds, userScrollableHorizontal, userScrollableVertical));
+
     // Initialize the context for current, absolute and fixed position cases.
     // They are the same, except that scroll translation does not apply to
     // fixed position descendants.
     context.current.transform = frameView.scrollTranslation();
     context.current.paintOffset = LayoutPoint();
     context.current.clip = frameView.contentClip();
+    context.current.scroll = frameView.scroll();
     context.current.renderingContextID = 0;
     context.current.shouldFlattenInheritedTransform = true;
     context.absolutePosition = context.current;
@@ -237,6 +252,7 @@ void PaintPropertyTreeBuilder::updateLocalBorderBoxContext(const LayoutObject& o
         wrapUnique(new ObjectPaintProperties::LocalBorderBoxProperties);
     borderBoxContext->paintOffset = context.current.paintOffset;
     borderBoxContext->propertyTreeState = PropertyTreeState(context.current.transform, context.current.clip, context.currentEffect);
+    borderBoxContext->scroll = context.current.scroll;
 
     if (!context.current.clip) {
         DCHECK(object.isLayoutView());
@@ -354,7 +370,7 @@ void PaintPropertyTreeBuilder::updateSvgLocalToBorderBoxTransform(const LayoutOb
     context.current.renderingContextID = 0;
 }
 
-void PaintPropertyTreeBuilder::updateScrollTranslation(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
+void PaintPropertyTreeBuilder::updateScrollAndScrollTranslation(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
 {
     if (object.isBoxModelObject() && object.hasOverflowClip()) {
         PaintLayer* layer = toLayoutBoxModelObject(object).layer();
@@ -365,13 +381,25 @@ void PaintPropertyTreeBuilder::updateScrollTranslation(const LayoutObject& objec
             TransformationMatrix matrix = TransformationMatrix().translate(-scrollOffset.width(), -scrollOffset.height());
             context.current.transform = object.getMutableForPainting().ensureObjectPaintProperties().createOrUpdateScrollTranslation(
                 context.current.transform, matrix, FloatPoint3D(), context.current.shouldFlattenInheritedTransform, context.current.renderingContextID);
+
+            // TODO(pdr): Set these values properly.
+            FloatSize scrollClip;
+            FloatSize scrollBounds;
+            bool userScrollableHorizontal = false;
+            bool userScrollableVertical = false;
+            context.current.scroll = object.getMutableForPainting().ensureObjectPaintProperties().createOrUpdateScroll(
+                context.current.scroll, context.current.transform, scrollClip, scrollBounds, userScrollableHorizontal, userScrollableVertical);
+
             context.current.shouldFlattenInheritedTransform = false;
             return;
         }
     }
 
-    if (ObjectPaintProperties* properties = object.getMutableForPainting().objectPaintProperties())
+    // TODO(pdr): Ensure non-scrollable objects get a scroll node that doesn't scroll.
+    if (ObjectPaintProperties* properties = object.getMutableForPainting().objectPaintProperties()) {
         properties->clearScrollTranslation();
+        properties->clearScroll();
+    }
 }
 
 void PaintPropertyTreeBuilder::updateOutOfFlowContext(const LayoutObject& object, PaintPropertyTreeBuilderContext& context)
@@ -485,7 +513,7 @@ void PaintPropertyTreeBuilder::buildTreeNodesForChildren(const LayoutObject& obj
     updateOverflowClip(object, context);
     updatePerspective(object, context);
     updateSvgLocalToBorderBoxTransform(object, context);
-    updateScrollTranslation(object, context);
+    updateScrollAndScrollTranslation(object, context);
     updateOutOfFlowContext(object, context);
 }