Drawing bounds should not be pixel-snapped.

Source/core/paint/LayoutObjectDrawingRecorder.h

Index: Source/core/paint/LayoutObjectDrawingRecorder.h
diff --git a/Source/core/paint/LayoutObjectDrawingRecorder.h b/Source/core/paint/LayoutObjectDrawingRecorder.h
index cd79523f73d4eafbec90f131847e5889286f5cae..99cd83193349b2a7c6715df4495905b37f4454da 100644
--- a/Source/core/paint/LayoutObjectDrawingRecorder.h
+++ b/Source/core/paint/LayoutObjectDrawingRecorder.h
@@ -43,7 +43,7 @@ public:
         : LayoutObjectDrawingRecorder(context, layoutObject, DisplayItem::paintPhaseToDrawingType(phase), clip) { }
 
     LayoutObjectDrawingRecorder(GraphicsContext& context, const LayoutObject& layoutObject, DisplayItem::Type type, const LayoutRect& clip)
-        : LayoutObjectDrawingRecorder(context, layoutObject, type, pixelSnappedIntRect(clip)) { }
+        : LayoutObjectDrawingRecorder(context, layoutObject, type, enclosingIntRect(clip)) { }

[jbroman, 2015/08/24 15:58:46]

Aside: This could arguably just be "clip", which does a conversion to FloatRect.
It's not clear to me why going to the integer pixel grid here is helpful.

So far I've just used enclosingIntRect because it seems like the smaller change.

 
 #if ENABLE(ASSERT)
     void setUnderInvalidationCheckingMode(DrawingDisplayItem::UnderInvalidationCheckingMode mode) { m_drawingRecorder->setUnderInvalidationCheckingMode(mode); }