Skip PaintPhaseFloat if no floats in a layer

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

Index: third_party/WebKit/Source/core/paint/PaintLayer.h
diff --git a/third_party/WebKit/Source/core/paint/PaintLayer.h b/third_party/WebKit/Source/core/paint/PaintLayer.h
index 2654734eaea7b8f6f2d52351d8ca4379e41c47b9..6a7de9b1b345751b7f42675f77c6c8c05e210fe4 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayer.h
+++ b/third_party/WebKit/Source/core/paint/PaintLayer.h
@@ -626,6 +626,9 @@ public:
     bool needsPaintPhaseDescendantOutlines() const { return m_needsPaintPhaseDescendantOutlines; }
     void setNeedsPaintPhaseDescendantOutlines() { ASSERT(isSelfPaintingLayer()); m_needsPaintPhaseDescendantOutlines = true; }
 
+    bool needsPaintPhaseFloat() const { return m_needsPaintPhaseFloat; }

[chrishtr, 2016/01/22 00:14:44]

Add a comment that once-float, always float.

[Xianzhu, 2016/01/22 00:50:24]

Added full comments in https://codereview.chromium.org/1584493002/ for
descendant outlines above, and add comment for this method referencing above.

+    void setNeedsPaintPhaseFloat() { ASSERT(isSelfPaintingLayer()); m_needsPaintPhaseFloat = true; }
+
     PaintTiming* paintTiming();
 
 private:
@@ -759,6 +762,7 @@ private:
     unsigned m_previousPaintResult : 1; // PaintLayerPainter::PaintResult
 
     unsigned m_needsPaintPhaseDescendantOutlines : 1;
+    unsigned m_needsPaintPhaseFloat : 1;
 
     LayoutBoxModelObject* m_layoutObject;