Fix several corner case issues of scrollbar paint invalidation

third_party/WebKit/Source/core/layout/compositing/PaintLayerCompositor.cpp

Index: third_party/WebKit/Source/core/layout/compositing/PaintLayerCompositor.cpp
diff --git a/third_party/WebKit/Source/core/layout/compositing/PaintLayerCompositor.cpp b/third_party/WebKit/Source/core/layout/compositing/PaintLayerCompositor.cpp
index 6d1bf5e6804f771ffa97a4784cc174588667985c..24a813867ef2fb216d1e9ea3979e863bbc0232c3 100644
--- a/third_party/WebKit/Source/core/layout/compositing/PaintLayerCompositor.cpp
+++ b/third_party/WebKit/Source/core/layout/compositing/PaintLayerCompositor.cpp
@@ -332,11 +332,11 @@ void PaintLayerCompositor::updateWithoutAcceleratedCompositing(CompositingUpdate
 
 static void forceRecomputePaintInvalidationRectsIncludingNonCompositingDescendants(LayoutObject* layoutObject)
 {
-    // We clear the previous paint invalidation rect as it's wrong (paint invaliation container
+    // We clear the previous paint invalidation rect as it's wrong (paint invalidation container
     // changed, ...). Forcing a full invalidation will make us recompute it. Also we are not
     // changing the previous position from our paint invalidation container, which is fine as
     // we want a full paint invalidation anyway.
-    layoutObject->setPreviousPaintInvalidationRect(LayoutRect());
+    layoutObject->clearPreviousPaintInvalidationRects();
     layoutObject->setShouldDoFullPaintInvalidation();
 
     for (LayoutObject* child = layoutObject->slowFirstChild(); child; child = child->nextSibling()) {