When setting needsRepaint, don't stop at non-stacking composited PaintLayers.

third_party/WebKit/Source/core/paint/PaintLayer.cpp

Index: third_party/WebKit/Source/core/paint/PaintLayer.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintLayer.cpp b/third_party/WebKit/Source/core/paint/PaintLayer.cpp
index 02e2e26be245aaf48b24b8f9119182efa6c378ba..65ae986ed17c162d8a8b16dfba43c49180d99433 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayer.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayer.cpp
@@ -918,6 +918,11 @@ LayoutPoint PaintLayer::computeOffsetFromTransformedAncestor() const {
 }
 
 PaintLayer* PaintLayer::compositingContainer() const {
+  // Floats have special paintinng order. Also, the container does not need
+  // to be a stacking context, because floats are not stacked.
+  if (m_layoutObject->isFloating() && m_layoutObject->parent() &&
+      !m_layoutObject->parent()->isLayoutBlockFlow())
+    return m_layoutObject->containingBlock()->enclosingLayer();
   if (!stackingNode()->isStacked())
     return parent();
   if (PaintLayerStackingNode* ancestorStackingNode =