Traverse into child LayoutViews during invalidateTreeIfNeeded

Source/core/layout/LayoutView.h

Index: Source/core/layout/LayoutView.h
diff --git a/Source/core/layout/LayoutView.h b/Source/core/layout/LayoutView.h
index fc6656e6e09877266402fb9992f7b8bdbde60808..2643894fd80fc2b9835231a8fa77fd635b786551 100644
--- a/Source/core/layout/LayoutView.h
+++ b/Source/core/layout/LayoutView.h
@@ -183,6 +183,11 @@ public:
 
     virtual LayoutRect visualOverflowRect() const override;
 
+    bool forceCheckForPaintInvalidationByParent() const { return !isPaintInvalidationContainer() && m_forceCheckForPaintInvalidationByParent; }
+    void setForceCheckForPaintInvalidationByParent(bool b) { ASSERT(!isPaintInvalidationContainer()); m_forceCheckForPaintInvalidationByParent = b; }
+    bool paintInvalidationCachedOffsetsEnabledByParent() const { return isPaintInvalidationContainer() || m_paintInvalidationCachedOffsetsEnabledByParent; }
+    void setPaintInvalidationCachedOffsetsEnabledByParent(bool b) { ASSERT(!isPaintInvalidationContainer()); m_paintInvalidationCachedOffsetsEnabledByParent = b; }
+
 private:
     virtual void mapLocalToContainer(const LayoutBoxModelObject* paintInvalidationContainer, TransformState&, MapCoordinatesFlags = ApplyContainerFlip, bool* wasFixed = nullptr, const PaintInvalidationState* = nullptr) const override;
 
@@ -227,6 +232,11 @@ private:
     OwnPtrWillBePersistent<HitTestCache> m_hitTestCache;
 
     OwnPtrWillBePersistent<PendingSelection> m_pendingSelection;
+
+    // Set during parent LayoutView's paint invalidation. Checked during its own paint invalidation.
+    // They are ignored if this LayoutView is paint invalidation container.
+    bool m_forceCheckForPaintInvalidationByParent;
+    bool m_paintInvalidationCachedOffsetsEnabledByParent;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutView, isLayoutView());