[SPv1] Always set a CompositorElementId on main graphics layers; use PaintLayer id.

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 <memory>
 #include "core/dom/DOMNodeIds.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
@@ skipping 54 matching lines @@
   if (auto* existing_content_clip = frame_view.ContentClip()) {
     existing_content_clip->Update(std::move(parent),
                                   std::move(local_transform_space), clip_rect);
     return false;
   }
   frame_view.SetContentClip(ClipPaintPropertyNode::Create(
       std::move(parent), std::move(local_transform_space), clip_rect));
   return true;
 }
 
-static CompositorElementId CreateDomNodeBasedCompositorElementId(
+static CompositorElementId CreatePaintLayereBasedCompositorElementId(
     const LayoutObject& object) {
-  // TODO(wkorman): Centralize this implementation with similar across
-  // animation, scrolling and compositing logic.
-  return CompositorElementIdFromDOMNodeId(
-      DOMNodeIds::IdForNode(object.GetNode()),
+  DCHECK(object.IsBoxModelObject() && object.HasLayer());
+  return CompositorElementIdFromPaintLayerId(
+      ToLayoutBoxModelObject(object).Layer()->UniqueId(),
       CompositorElementIdNamespace::kPrimary);
 }
 
 // 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 UpdateScrollTranslation(
     FrameView& frame_view,
     PassRefPtr<const TransformPaintPropertyNode> parent,
     const TransformationMatrix& matrix,
     const FloatPoint3D& origin,
     PassRefPtr<const ScrollPaintPropertyNode> scroll_parent,
     const IntSize& clip,
     const IntSize& bounds,
     bool user_scrollable_horizontal,
     bool user_scrollable_vertical,
     MainThreadScrollingReasons main_thread_scrolling_reasons,
     WebLayerScrollClient* scroll_client) {
   DCHECK(!RuntimeEnabledFeatures::rootLayerScrollingEnabled());
   CompositorElementId compositor_element_id =
-      CreateDomNodeBasedCompositorElementId(*frame_view.GetLayoutView());
+      CreatePaintLayereBasedCompositorElementId(*frame_view.GetLayoutView());
   if (auto* existing_scroll_translation = frame_view.ScrollTranslation()) {
     auto existing_reasons = existing_scroll_translation->ScrollNode()
                                 ->GetMainThreadScrollingReasons();
     existing_scroll_translation->UpdateScrollTranslation(
         std::move(parent), matrix, origin, false, 0, kCompositingReasonNone,
         compositor_element_id, std::move(scroll_parent), clip, bounds,
         user_scrollable_horizontal, user_scrollable_vertical,
         main_thread_scrolling_reasons, scroll_client);
     return existing_reasons != main_thread_scrolling_reasons;
   }
@@ skipping 1077 matching lines @@
       NeedsFilter(object) || NeedsCssClip(object) ||
       NeedsScrollbarPaintOffset(object) || NeedsOverflowClip(object) ||
       NeedsPerspective(object) || NeedsSVGLocalToBorderBoxTransform(object) ||
       NeedsScrollTranslation(object) || NeedsCssClipFixedPosition(object);
 
   bool had_paint_properties = object.PaintProperties();
 
   if (needs_paint_properties && !had_paint_properties) {
     ObjectPaintProperties& paint_properties =
         object.GetMutableForPainting().EnsurePaintProperties();
-    if (RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {
+    if (RuntimeEnabledFeatures::slimmingPaintV2Enabled() && object.HasLayer()) {
       paint_properties.SetCompositorElementId(
-          CreateDomNodeBasedCompositorElementId(object));
+          CreatePaintLayereBasedCompositorElementId(object));
     }
   } else if (!needs_paint_properties && had_paint_properties) {
     object.GetMutableForPainting().ClearPaintProperties();
     full_context.force_subtree_update = true;
   }
 }
 
 static inline bool ObjectTypeMightNeedPaintProperties(
     const LayoutObject& object) {
   return object.IsBoxModelObject() || object.IsSVG();
@@ skipping 69 matching lines @@
                            context.force_subtree_update);
 
     context.force_subtree_update |= object.SubtreeNeedsPaintPropertyUpdate();
   }
 
   if (object.CanContainAbsolutePositionObjects())
     context.container_for_absolute_position = &object;
 }
 
 }  // namespace blink