Optimize visual overflow computation code by devirtualizing some methods.

Before this patch, ComputeVisualOverflow() was virtual, and so was
AddVisualOverflowFromChildren(), which was called by
ComputeVisualOverflow(). This pattern existed to share a bit more
code with LayoutBlock other than the code to collect rects from
children. This CL instead inlines the duplicated code in a few places
and de-virtualizes AddVisualOverflowFromChildren.

Bug: 894244

Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_layout_ng
Change-Id: Ic9e36c0271ac6d88ee660e9113e1a2b7db8e0148
Reviewed-on: https://chromium-review.googlesource.com/c/1281234Reviewed-by: Stephen Chenney <schenney@chromium.org>
Commit-Queue: Chris Harrelson <chrishtr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#600156}

third_party/blink/renderer/core/layout/layout_block.h

@@ -449,11 +449,11 @@ class CORE_EXPORT LayoutBlock : public LayoutBox {
 
  private:
   void AddVisualOverflowFromBlockChildren();
-  void AddVisualOverflowFromTheme();
   void AddLayoutOverflowFromPositionedObjects();
   void AddLayoutOverflowFromBlockChildren();
 
  protected:
+  void AddVisualOverflowFromTheme();
   virtual void ComputeVisualOverflow(
       const LayoutRect& previous_visual_overflow_rect,
       bool recompute_floats);
@@ -461,7 +461,7 @@ class CORE_EXPORT LayoutBlock : public LayoutBox {
                                      bool recompute_floats);
 
   virtual void AddLayoutOverflowFromChildren();
-  virtual void AddVisualOverflowFromChildren();
+  void AddVisualOverflowFromChildren();
 
   void AddOutlineRects(Vector<LayoutRect>&,
                        const LayoutPoint& additional_offset,

third_party/blink/renderer/core/layout/layout_block_flow.cc

@@ -2566,11 +2566,20 @@ void LayoutBlockFlow::UpdatePaintFragmentFromCachedLayoutResult(
 void LayoutBlockFlow::ComputeVisualOverflow(
     const LayoutRect& previous_visual_overflow_rect,
     bool recompute_floats) {
-  LayoutBlock::ComputeVisualOverflow(previous_visual_overflow_rect,
-                                     recompute_floats);
+  AddVisualOverflowFromChildren();
+
+  AddVisualEffectOverflow();
+  AddVisualOverflowFromTheme();
+
   if (recompute_floats || CreatesNewFormattingContext() ||
       HasSelfPaintingLayer())
     AddVisualOverflowFromFloats();
+
+  if (VisualOverflowRect() != previous_visual_overflow_rect) {
+    if (Layer())
+      Layer()->SetNeedsCompositingInputsUpdate();
+    GetFrameView()->SetIntersectionObservationState(LocalFrameView::kDesired);
+  }
 }
 
 void LayoutBlockFlow::ComputeLayoutOverflow(LayoutUnit old_client_after_edge,

third_party/blink/renderer/core/layout/layout_list_item.cc

@@ -29,6 +29,7 @@
 #include "third_party/blink/renderer/core/html_names.h"
 #include "third_party/blink/renderer/core/layout/layout_list_marker.h"
 #include "third_party/blink/renderer/core/paint/list_item_painter.h"
+#include "third_party/blink/renderer/core/paint/paint_layer.h"
 #include "third_party/blink/renderer/platform/wtf/saturated_arithmetic.h"
 #include "third_party/blink/renderer/platform/wtf/std_lib_extras.h"
 #include "third_party/blink/renderer/platform/wtf/text/string_builder.h"
@@ -289,6 +290,25 @@ bool LayoutListItem::UpdateMarkerLocation() {
   return false;
 }
 
+void LayoutListItem::ComputeVisualOverflow(
+    const LayoutRect& previous_visual_overflow_rect,
+    bool recompute_floats) {
+  AddVisualOverflowFromChildren();
+
+  AddVisualEffectOverflow();
+  AddVisualOverflowFromTheme();
+
+  if (recompute_floats || CreatesNewFormattingContext() ||
+      HasSelfPaintingLayer())
+    AddVisualOverflowFromFloats();
+
+  if (VisualOverflowRect() != previous_visual_overflow_rect) {
+    if (Layer())
+      Layer()->SetNeedsCompositingInputsUpdate();
+    GetFrameView()->SetIntersectionObservationState(LocalFrameView::kDesired);
+  }
+}
+
 void LayoutListItem::AddVisualOverflowFromChildren() {
   LayoutBlockFlow::AddVisualOverflowFromChildren();
   UpdateOverflow(Visual);

third_party/blink/renderer/core/layout/layout_list_item.h

@@ -70,7 +70,9 @@ class LayoutListItem final : public LayoutBlockFlow {
 
   void StyleDidChange(StyleDifference, const ComputedStyle* old_style) override;
 
-  void AddVisualOverflowFromChildren() override;
+  void ComputeVisualOverflow(const LayoutRect&, bool recompute_floats) final;
+
+  void AddVisualOverflowFromChildren();
   void AddLayoutOverflowFromChildren() override;
 
   void AlignMarkerInBlockDirection();

third_party/blink/renderer/core/layout/layout_multi_column_set.cc

@@ -29,6 +29,7 @@
 #include "third_party/blink/renderer/core/layout/layout_multi_column_flow_thread.h"
 #include "third_party/blink/renderer/core/layout/multi_column_fragmentainer_group.h"
 #include "third_party/blink/renderer/core/paint/multi_column_set_painter.h"
+#include "third_party/blink/renderer/core/paint/paint_layer.h"
 
 namespace blink {
 
@@ -520,6 +521,25 @@ LayoutRect LayoutMultiColumnSet::FragmentsBoundingBox(
   return result;
 }
 
+void LayoutMultiColumnSet::ComputeVisualOverflow(
+    const LayoutRect& previous_visual_overflow_rect,
+    bool recompute_floats) {
+  AddVisualOverflowFromChildren();
+
+  AddVisualEffectOverflow();
+  AddVisualOverflowFromTheme();
+
+  if (recompute_floats || CreatesNewFormattingContext() ||
+      HasSelfPaintingLayer())
+    AddVisualOverflowFromFloats();
+
+  if (VisualOverflowRect() != previous_visual_overflow_rect) {
+    if (Layer())
+      Layer()->SetNeedsCompositingInputsUpdate();
+    GetFrameView()->SetIntersectionObservationState(LocalFrameView::kDesired);
+  }
+}
+
 void LayoutMultiColumnSet::AddVisualOverflowFromChildren() {
   // It's useless to calculate overflow if we haven't determined the page
   // logical height yet.

third_party/blink/renderer/core/layout/layout_multi_column_set.h

@@ -255,7 +255,9 @@ class CORE_EXPORT LayoutMultiColumnSet : public LayoutBlockFlow {
   void PaintObject(const PaintInfo&,
                    const LayoutPoint& paint_offset) const override;
 
-  void AddVisualOverflowFromChildren() override;
+  void ComputeVisualOverflow(const LayoutRect&, bool recompute_floats) final;
+
+  void AddVisualOverflowFromChildren();
   void AddLayoutOverflowFromChildren() override;
 
   MultiColumnFragmentainerGroupList fragmentainer_groups_;

third_party/blink/renderer/core/layout/layout_table.cc

@@ -910,6 +910,21 @@ void LayoutTable::InvalidateCollapsedBordersForAllCellsIfNeeded() {
   }
 }
 
+void LayoutTable::ComputeVisualOverflow(
+    const LayoutRect& previous_visual_overflow_rect,
+    bool recompute_floats) {
+  AddVisualOverflowFromChildren();
+
+  AddVisualEffectOverflow();
+  AddVisualOverflowFromTheme();
+
+  if (VisualOverflowRect() != previous_visual_overflow_rect) {
+    if (Layer())
+      Layer()->SetNeedsCompositingInputsUpdate();
+    GetFrameView()->SetIntersectionObservationState(LocalFrameView::kDesired);
+  }
+}
+
 void LayoutTable::AddVisualOverflowFromChildren() {
   // Add overflow from borders.
   // Technically it's odd that we are incorporating the borders into layout

third_party/blink/renderer/core/layout/layout_table.h

@@ -474,7 +474,9 @@ class CORE_EXPORT LayoutTable final : public LayoutBlock {
       OverlayScrollbarClipBehavior =
           kIgnorePlatformOverlayScrollbarSize) const override;
 
-  void AddVisualOverflowFromChildren() override;
+  void ComputeVisualOverflow(const LayoutRect&, bool recompute_floats) final;
+
+  void AddVisualOverflowFromChildren();
   void AddLayoutOverflowFromChildren() override;
 
   void RecalcSections() const;

third_party/blink/renderer/core/layout/layout_text_control_single_line.cc

@@ -34,6 +34,7 @@
 #include "third_party/blink/renderer/core/layout/hit_test_result.h"
 #include "third_party/blink/renderer/core/layout/layout_analyzer.h"
 #include "third_party/blink/renderer/core/layout/layout_theme.h"
+#include "third_party/blink/renderer/core/paint/paint_layer.h"
 #include "third_party/blink/renderer/core/paint/text_control_single_line_painter.h"
 #include "third_party/blink/renderer/platform/fonts/simple_font_data.h"
 
@@ -317,4 +318,23 @@ HTMLInputElement* LayoutTextControlSingleLine::InputElement() const {
   return ToHTMLInputElement(GetNode());
 }
 
+void LayoutTextControlSingleLine::ComputeVisualOverflow(
+    const LayoutRect& previous_visual_overflow_rect,
+    bool recompute_floats) {
+  AddVisualOverflowFromChildren();
+
+  AddVisualEffectOverflow();
+  AddVisualOverflowFromTheme();
+
+  if (recompute_floats || CreatesNewFormattingContext() ||
+      HasSelfPaintingLayer())
+    AddVisualOverflowFromFloats();
+
+  if (VisualOverflowRect() != previous_visual_overflow_rect) {
+    if (Layer())
+      Layer()->SetNeedsCompositingInputsUpdate();
+    GetFrameView()->SetIntersectionObservationState(LocalFrameView::kDesired);
+  }
+}
+
 }  // namespace blink

third_party/blink/renderer/core/layout/layout_text_control_single_line.h

@@ -78,10 +78,11 @@ class LayoutTextControlSingleLine : public LayoutTextControl {
       LayoutUnit line_height,
       LayoutUnit non_content_height) const override;
 
+  void ComputeVisualOverflow(const LayoutRect&, bool recompute_floats) override;
+
   // If the INPUT content height is smaller than the font height, the
   // inner-editor element overflows the INPUT box intentionally, however it
   // shouldn't affect outside of the INPUT box.  So we ignore child overflow.
-  void AddVisualOverflowFromChildren() final {}
   void AddLayoutOverflowFromChildren() final {}
 
   bool AllowsOverflowClip() const override { return false; }

third_party/blink/renderer/core/layout/ng/layout_ng_mixin.cc

@@ -19,6 +19,7 @@
 #include "third_party/blink/renderer/core/layout/ng/ng_relative_utils.h"
 #include "third_party/blink/renderer/core/paint/ng/ng_block_flow_painter.h"
 #include "third_party/blink/renderer/core/paint/ng/ng_paint_fragment.h"
+#include "third_party/blink/renderer/core/paint/paint_layer.h"
 
 namespace blink {
 
@@ -65,6 +66,21 @@ const NGPhysicalBoxFragment* LayoutNGMixin<Base>::CurrentFragment() const {
   return nullptr;
 }
 
+template <typename Base>
+void LayoutNGMixin<Base>::ComputeVisualOverflow(
+    const LayoutRect& previous_visual_overflow_rect,
+    bool recompute_floats) {
+  Base::ComputeVisualOverflow(previous_visual_overflow_rect, recompute_floats);
+  AddVisualOverflowFromChildren();
+
+  if (Base::VisualOverflowRect() != previous_visual_overflow_rect) {
+    if (Base::Layer())
+      Base::Layer()->SetNeedsCompositingInputsUpdate();
+    Base::GetFrameView()->SetIntersectionObservationState(
+        LocalFrameView::kDesired);
+  }
+}
+
 template <typename Base>
 void LayoutNGMixin<Base>::AddVisualOverflowFromChildren() {
   // |ComputeOverflow()| calls this, which is called from

third_party/blink/renderer/core/layout/ng/layout_ng_mixin.h

@@ -83,7 +83,9 @@ class LayoutNGMixin : public Base {
  protected:
   bool IsOfType(LayoutObject::LayoutObjectType) const override;
 
-  void AddVisualOverflowFromChildren() final;
+  void ComputeVisualOverflow(const LayoutRect&, bool recompute_floats) final;
+
+  void AddVisualOverflowFromChildren();
   void AddLayoutOverflowFromChildren() final;
 
  private: