Make LayerRepaintRects internal to RenderLayer

https://bugs.webkit.org/show_bug.cgi?id=264530
rdar://118203951

Reviewed by Chris Dumez.

There are two call sites that make use of RenderLayer's cached repaint rects, but
they both use only the clippedOverflowRect, not the outlineBoundsRect, so we can
hide RepaintRects inside of RenderLayer, and only expose the cachedClippedOverflowRect()
to those two clients.

* Source/WebCore/rendering/LegacyLineLayout.cpp:
(WebCore::LegacyLineLayout::layoutRunsAndFloats):
* Source/WebCore/rendering/RenderLayer.cpp:
(WebCore::RenderLayer::cachedClippedOverflowRect const):
(WebCore::RenderLayer::setRepaintRects):
(WebCore::RenderLayer::shouldRepaintAfterLayout const):
* Source/WebCore/rendering/RenderLayer.h:
(WebCore::RenderLayer::repaintRects const):
* Source/WebCore/rendering/RenderLayerModelObject.cpp:
(WebCore::RenderLayerModelObject::styleDidChange):
(WebCore::RenderLayerModelObject::cachedLayerClippedOverflowRect const):
(WebCore::RenderLayerModelObject::layerRepaintRects const): Deleted.
* Source/WebCore/rendering/RenderLayerModelObject.h:
* Source/WebCore/rendering/RenderLayerScrollableArea.cpp:
(WebCore::RenderLayerScrollableArea::scrollTo):

Canonical link: https://commits.webkit.org/270550@main

Source/WebCore/rendering/LegacyLineLayout.cpp

@@ -1333,12 +1333,12 @@ void LegacyLineLayout::layoutRunsAndFloats(LineLayoutState& layoutState, bool ha
     // determineStartPosition first will break fast/repaint/line-flow-with-floats-9.html.
     if (layoutState.isFullLayout() && hasInlineChild && !m_flow.selfNeedsLayout()) {
         m_flow.setNeedsLayout(MarkOnlyThis); // Mark as needing a full layout to force us to repaint.
-        if (!layoutContext().needsFullRepaint() && m_flow.layerRepaintRects()) {
+        if (!layoutContext().needsFullRepaint() && m_flow.cachedLayerClippedOverflowRect()) {
             // Because we waited until we were already inside layout to discover
             // that the block really needed a full layout, we missed our chance to repaint the layer
             // before layout started. Luckily the layer has cached the repaint rect for its original
             // position and size, and so we can use that to make a repaint happen now.
-            m_flow.repaintUsingContainer(m_flow.containerForRepaint().renderer.get(), m_flow.layerRepaintRects()->clippedOverflowRect);
+            m_flow.repaintUsingContainer(m_flow.containerForRepaint().renderer.get(), *m_flow.cachedLayerClippedOverflowRect());
         }
     }
 

Source/WebCore/rendering/RenderLayer.cpp

@@ -1164,6 +1164,14 @@ void RenderLayer::dirtyAncestorChainHasSelfPaintingLayerDescendantStatus()
     }
 }
 
+std::optional<LayoutRect> RenderLayer::cachedClippedOverflowRect() const
+{
+    if (!m_repaintRectsValid)
+        return std::nullopt;
+
+    return m_repaintRects.clippedOverflowRect;
+}
+
 void RenderLayer::computeRepaintRects(const RenderLayerModelObject* repaintContainer, const RenderGeometryMap* geometryMap)
 {
     ASSERT(!m_visibleContentStatusDirty);
@@ -1189,7 +1197,7 @@ void RenderLayer::computeRepaintRectsIncludingDescendants()
         layer->computeRepaintRectsIncludingDescendants();
 }
 
-void RenderLayer::setRepaintRects(const LayerRepaintRects& rects)
+void RenderLayer::setRepaintRects(const RepaintRects& rects)
 {
     m_repaintRects = rects;
     m_repaintRectsValid = true;
@@ -2026,7 +2034,7 @@ RenderLayer* RenderLayer::enclosingTransformedAncestor() const
     return curr;
 }
 
-inline bool RenderLayer::shouldRepaintAfterLayout() const
+bool RenderLayer::shouldRepaintAfterLayout() const
 {
 #if ENABLE(LAYER_BASED_SVG_ENGINE)
     // The SVG containers themselves never trigger repaints, only their contents are allowed to.

Source/WebCore/rendering/RenderLayer.h

@@ -220,13 +220,7 @@ class RenderLayer : public CanMakeWeakPtr<RenderLayer>, public CanMakeCheckedPtr
 
     RenderLayer* paintOrderParent() const;
 
-    std::optional<LayerRepaintRects> repaintRects() const
-    {
-        if (m_repaintRectsValid)
-            return m_repaintRects;
-
-        return { };
-    }
+    std::optional<LayoutRect> cachedClippedOverflowRect() const;
 
     void dirtyNormalFlowList();
     void dirtyZOrderLists();
@@ -969,10 +963,24 @@ class RenderLayer : public CanMakeWeakPtr<RenderLayer>, public CanMakeCheckedPtr
     void setAncestorChainHasSelfPaintingLayerDescendant();
     void dirtyAncestorChainHasSelfPaintingLayerDescendantStatus();
 
+    struct RepaintRects {
+        LayoutRect clippedOverflowRect;
+        LayoutRect outlineBoundsRect;
+    };
+
+
+    std::optional<RepaintRects> repaintRects() const
+    {
+        if (m_repaintRectsValid)
+            return m_repaintRects;
+
+        return { };
+    }
+
     void computeRepaintRects(const RenderLayerModelObject* repaintContainer, const RenderGeometryMap* = nullptr);
     void computeRepaintRectsIncludingDescendants();
 
-    void setRepaintRects(const LayerRepaintRects&);
+    void setRepaintRects(const RepaintRects&);
     void clearRepaintRects();
 
     LayoutRect clipRectRelativeToAncestor(RenderLayer* ancestor, LayoutSize offsetFromAncestor, const LayoutRect& constrainingRect) const;
@@ -1310,7 +1318,7 @@ class RenderLayer : public CanMakeWeakPtr<RenderLayer>, public CanMakeCheckedPtr
     std::unique_ptr<Vector<RenderLayer*>> m_normalFlowList;
 
     // Only valid if m_repaintRectsValid is set (std::optional<> not used to avoid padding).
-    LayerRepaintRects m_repaintRects;
+    RepaintRects m_repaintRects;
 
     // Our current relative or absolute position offset.
     LayoutSize m_offsetForPosition;

Source/WebCore/rendering/RenderLayerModelObject.cpp

@@ -175,8 +175,8 @@ void RenderLayerModelObject::styleDidChange(StyleDifference diff, const RenderSt
         setHasReflection(false);
 
         // Repaint the about to be destroyed self-painting layer when style change also triggers repaint.
-        if (layer()->isSelfPaintingLayer() && layer()->repaintStatus() == RepaintStatus::NeedsFullRepaint && layer()->repaintRects())
-            repaintUsingContainer(containerForRepaint().renderer.get(), layer()->repaintRects()->clippedOverflowRect);
+        if (layer()->isSelfPaintingLayer() && layer()->repaintStatus() == RepaintStatus::NeedsFullRepaint && layer()->cachedClippedOverflowRect())
+            repaintUsingContainer(containerForRepaint().renderer.get(), *(layer()->cachedClippedOverflowRect()));
 
         layer()->removeOnlyThisLayer(RenderLayer::LayerChangeTiming::StyleChange); // calls destroyLayer() which clears m_layer
         if (s_wasFloating && isFloating())
@@ -238,9 +238,9 @@ bool RenderLayerModelObject::shouldPlaceVerticalScrollbarOnLeft() const
 #endif
 }
 
-std::optional<LayerRepaintRects> RenderLayerModelObject::layerRepaintRects() const
+std::optional<LayoutRect> RenderLayerModelObject::cachedLayerClippedOverflowRect() const
 {
-    return hasLayer() ? layer()->repaintRects() : std::nullopt;
+    return hasLayer() ? layer()->cachedClippedOverflowRect() : std::nullopt;
 }
 
 bool RenderLayerModelObject::startAnimation(double timeOffset, const Animation& animation, const KeyframeList& keyframes)

Source/WebCore/rendering/RenderLayerModelObject.h

@@ -32,11 +32,6 @@ class KeyframeList;
 class RenderLayer;
 class SVGGraphicsElement;
 
-struct LayerRepaintRects {
-    LayoutRect clippedOverflowRect;
-    LayoutRect outlineBoundsRect;
-};
-
 class RenderLayerModelObject : public RenderElement {
     WTF_MAKE_ISO_ALLOCATED(RenderLayerModelObject);
 public:
@@ -65,7 +60,7 @@ class RenderLayerModelObject : public RenderElement {
 
     bool shouldPlaceVerticalScrollbarOnLeft() const;
 
-    std::optional<LayerRepaintRects> layerRepaintRects() const;
+    std::optional<LayoutRect> cachedLayerClippedOverflowRect() const;
 
     bool startAnimation(double timeOffset, const Animation&, const KeyframeList&) override;
     void animationPaused(double timeOffset, const String& name) override;

Source/WebCore/rendering/RenderLayerScrollableArea.cpp

@@ -388,7 +388,7 @@ void RenderLayerScrollableArea::scrollTo(const ScrollPosition& position)
     // The caret rect needs to be invalidated after scrolling
     frame.selection().setCaretRectNeedsUpdate();
 
-    LayoutRect rectForRepaint = layer().repaintRects() ? layer().repaintRects()->clippedOverflowRect : renderer.clippedOverflowRectForRepaint(repaintContainer.get());
+    auto rectForRepaint = valueOrCompute(layer().cachedClippedOverflowRect(), [&] { return renderer.clippedOverflowRectForRepaint(repaintContainer.get()); });
 
     FloatQuad quadForFakeMouseMoveEvent = FloatQuad(rectForRepaint);
     if (repaintContainer)