[RLS] Remove the RootLayerScrollingEnabled check from FramePainter and PLSA.

Bug: 823365
Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: Ia97f4fac5a0fd9929d8ff03b109057db7171e8f3
Reviewed-on: https://chromium-review.googlesource.com/1070621
Commit-Queue: Chris Harrelson <chrishtr@chromium.org>
Reviewed-by: Philip Rogers <pdr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#561331}

third_party/blink/renderer/core/paint/frame_painter.cc

@@ -43,18 +43,9 @@ void FramePainter::Paint(GraphicsContext& context,
                                           GetFrameView().VisibleContentSize());
   IntPoint content_offset =
       -frame_view_location + GetFrameView().ScrollOffsetInt();
-  if (RuntimeEnabledFeatures::SlimmingPaintV2Enabled() &&
-      !RuntimeEnabledFeatures::RootLayerScrollingEnabled()) {
-    auto content_cull_rect = rect;
-    content_cull_rect.UpdateForScrollingContents(
-        visible_area_without_scrollbars,
-        AffineTransform().Translate(-content_offset.X(), -content_offset.Y()));
-    document_dirty_rect = content_cull_rect.rect_;
-  } else {
-    document_dirty_rect = rect.rect_;
-    document_dirty_rect.Intersect(visible_area_without_scrollbars);
-    document_dirty_rect.MoveBy(content_offset);
-  }
+  document_dirty_rect = rect.rect_;
+  document_dirty_rect.Intersect(visible_area_without_scrollbars);
+  document_dirty_rect.MoveBy(content_offset);
 
   bool should_paint_contents = !document_dirty_rect.IsEmpty();
   bool should_paint_scrollbars = !GetFrameView().ScrollbarsSuppressed() &&
@@ -75,28 +66,6 @@ void FramePainter::Paint(GraphicsContext& context,
                                GetFrameView().VisibleContentRect());
     PaintContents(context, global_paint_flags, document_dirty_rect);
   }
-
-  if (should_paint_scrollbars) {
-    DCHECK(!RuntimeEnabledFeatures::RootLayerScrollingEnabled());
-    IntRect scroll_view_dirty_rect = rect.rect_;
-    IntRect visible_area_with_scrollbars(
-        frame_view_location,
-        GetFrameView().VisibleContentSize(kIncludeScrollbars));
-    scroll_view_dirty_rect.Intersect(visible_area_with_scrollbars);
-    scroll_view_dirty_rect.MoveBy(-frame_view_location);
-
-    TransformRecorder transform_recorder(
-        context, *GetFrameView().GetLayoutView(),
-        AffineTransform::Translation(frame_view_location.X(),
-                                     frame_view_location.Y()));
-
-    ClipRecorder recorder(
-        context, *GetFrameView().GetLayoutView(),
-        DisplayItem::kClipFrameScrollbars,
-        IntRect(IntPoint(), visible_area_with_scrollbars.Size()));
-
-    PaintScrollbars(context, scroll_view_dirty_rect);
-  }
 }
 
 void FramePainter::PaintContents(GraphicsContext& context,

third_party/blink/renderer/core/paint/paint_layer_scrollable_area.cc

@@ -492,13 +492,8 @@ void PaintLayerScrollableArea::UpdateScrollOffset(
   InvalidatePaintForScrollOffsetChange(offset_was_zero);
 
   // The scrollOffsetTranslation paint property depends on the scroll offset.
-  // (see: PaintPropertyTreeBuilder.updateProperties(LocalFrameView&,...) and
-  // PaintPropertyTreeBuilder.updateScrollAndScrollTranslation).
-  if (!RuntimeEnabledFeatures::RootLayerScrollingEnabled() && is_root_layer) {
-    frame_view->SetNeedsPaintPropertyUpdate();
-  } else {
-    GetLayoutBox()->SetNeedsPaintPropertyUpdate();
-  }
+  // (see: PaintPropertyTreeBuilder::UpdateScrollAndScrollTranslation).
+  GetLayoutBox()->SetNeedsPaintPropertyUpdate();
 
   // Schedule the scroll DOM event.
   if (GetLayoutBox()->GetNode()) {
@@ -864,13 +859,6 @@ int PaintLayerScrollableArea::PixelSnappedScrollHeight() const {
 }
 
 void PaintLayerScrollableArea::UpdateScrollOrigin() {
-  // LayoutView doesn't scroll when RLS is turned off so we should avoid
-  // changing the scroll origin in that case as it can affect coordinate
-  // conversions.
-  if (!RuntimeEnabledFeatures::RootLayerScrollingEnabled() && GetLayoutBox() &&
-      GetLayoutBox()->IsLayoutView())
-    return;
-
   // This should do nothing prior to first layout; the if-clause will catch
   // that.
   if (OverflowRect().IsEmpty())
@@ -1164,9 +1152,7 @@ bool PaintLayerScrollableArea::HasVerticalOverflow() const {
 // overflow. Currently, we need to avoid producing scrollbars here if they'll be
 // handled externally in the RLC.
 static bool CanHaveOverflowScrollbars(const LayoutBox& box) {
-  return (RuntimeEnabledFeatures::RootLayerScrollingEnabled() ||
-          !box.IsLayoutView()) &&
-         box.GetDocument().ViewportDefiningElement() != box.GetNode();
+  return box.GetDocument().ViewportDefiningElement() != box.GetNode();
 }
 
 void PaintLayerScrollableArea::UpdateAfterStyleChange(
@@ -2156,11 +2142,10 @@ void PaintLayerScrollableArea::UpdateCompositingLayersAfterScroll() {
     if (HasStickyDescendants())
       InvalidateAllStickyConstraints();
 
-    // If we have fixed elements and we scroll the root layer in RLS we might
+    // If we have fixed elements and we scroll the root layer we might
     // change compositing since the fixed elements might now overlap a
     // composited layer.
-    if (Layer()->IsRootLayer() &&
-        RuntimeEnabledFeatures::RootLayerScrollingEnabled()) {
+    if (Layer()->IsRootLayer()) {
       LocalFrame* frame = GetLayoutBox()->GetFrame();
       if (frame && frame->View() &&
           frame->View()->HasViewportConstrainedObjects()) {