Add compositor element id for scroll nodes in 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/dom/DOMNodeIds.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
@@ skipping 68 matching lines @@
   DCHECK(!RuntimeEnabledFeatures::rootLayerScrollingEnabled());
   if (auto* existingScrollTranslation = frameView.scrollTranslation()) {
     existingScrollTranslation->update(std::move(parent), matrix, origin);
     return false;
   }
   frameView.setScrollTranslation(
       TransformPaintPropertyNode::create(std::move(parent), matrix, origin));
   return true;
 }
 
+static CompositorElementId createDomNodeBasedCompositorElementId(
+    const LayoutObject& object) {
+  return createCompositorElementId(DOMNodeIds::idForNode(object.node()),
+                                   CompositorSubElementId::Primary);
+}
+
 // True if a new property was created or a main thread scrolling reason changed
 // (which can affect descendants), false if an existing one was updated.
 static bool updateScroll(
     FrameView& frameView,
     PassRefPtr<const ScrollPaintPropertyNode> parent,
     PassRefPtr<const TransformPaintPropertyNode> scrollOffset,
     const IntSize& clip,
     const IntSize& bounds,
     bool userScrollableHorizontal,
     bool userScrollableVertical,
     MainThreadScrollingReasons mainThreadScrollingReasons) {
   DCHECK(!RuntimeEnabledFeatures::rootLayerScrollingEnabled());
+
+  CompositorElementId compositorElementId =
+      createDomNodeBasedCompositorElementId(*frameView.layoutView());
   if (auto* existingScroll = frameView.scroll()) {
     auto existingReasons = existingScroll->mainThreadScrollingReasons();
     existingScroll->update(std::move(parent), std::move(scrollOffset), clip,
                            bounds, userScrollableHorizontal,
-                           userScrollableVertical, mainThreadScrollingReasons);
+                           userScrollableVertical, mainThreadScrollingReasons,
+                           compositorElementId);
     return existingReasons != mainThreadScrollingReasons;
   }
   frameView.setScroll(ScrollPaintPropertyNode::create(
       std::move(parent), std::move(scrollOffset), clip, bounds,
       userScrollableHorizontal, userScrollableVertical,
-      mainThreadScrollingReasons));
+      mainThreadScrollingReasons, compositorElementId));
   return true;
 }
 
 static MainThreadScrollingReasons mainThreadScrollingReasons(
     const FrameView& frameView,
     MainThreadScrollingReasons ancestorReasons) {
   auto reasons = ancestorReasons;
   if (!frameView.frame().settings()->getThreadedScrollingEnabled())
     reasons |= MainThreadScrollingReason::kThreadedScrollingDisabled;
   if (frameView.hasBackgroundAttachmentFixedObjects())
@@ skipping 220 matching lines @@
   // Transform origin has no effect without a transform or motion path.
   if (!style.hasTransform())
     return FloatPoint3D();
   FloatSize borderBoxSize(box.size());
   return FloatPoint3D(
       floatValueForLength(style.transformOriginX(), borderBoxSize.width()),
       floatValueForLength(style.transformOriginY(), borderBoxSize.height()),
       style.transformOriginZ());
 }
 
-static CompositorElementId createDomNodeBasedCompositorElementId(
-    const LayoutObject& object) {
-  return createCompositorElementId(DOMNodeIds::idForNode(object.node()),
-                                   CompositorSubElementId::Primary);
-}
-
 void PaintPropertyTreeBuilder::updateTransform(
     const LayoutObject& object,
     PaintPropertyTreeBuilderContext& context) {
   if (object.isSVGChild()) {
     updateTransformForNonRootSVG(object, context);
     return;
   }
 
   if (object.needsPaintPropertyUpdate() || context.forceSubtreeUpdate) {
     const ComputedStyle& style = object.styleRef();
@@ skipping 419 matching lines @@
         bool userScrollableVertical =
             scrollableArea->userInputScrollable(VerticalScrollbar);
 
         // Main thread scrolling reasons depend on their ancestor's reasons
         // so ensure the entire subtree is updated when reasons change.
         if (auto* existingScrollNode = properties.scroll()) {
           if (existingScrollNode->mainThreadScrollingReasons() != reasons)
             context.forceSubtreeUpdate = true;
         }
 
+        CompositorElementId compositorElementId =
+            createDomNodeBasedCompositorElementId(object);
+
         context.forceSubtreeUpdate |= properties.updateScroll(
             context.current.scroll, properties.scrollTranslation(), scrollClip,
             scrollBounds, userScrollableHorizontal, userScrollableVertical,
-            reasons);
+            reasons, compositorElementId);
       }
     }
 
     if (!needsScrollProperties) {
       // Ensure pre-existing properties are cleared.
       if (auto* properties = object.getMutableForPainting().paintProperties()) {
         context.forceSubtreeUpdate |= properties->clearScrollTranslation();
         context.forceSubtreeUpdate |= properties->clearScroll();
       }
     }
@@ skipping 180 matching lines @@
   updateOverflowClip(object, context);
   updatePerspective(object, context);
   updateSvgLocalToBorderBoxTransform(object, context);
   updateScrollAndScrollTranslation(object, context);
   updateOutOfFlowContext(object, context);
 
   context.forceSubtreeUpdate |= object.subtreeNeedsPaintPropertyUpdate();
 }
 
 }  // namespace blink