Use enclosingIntRect instead of pixelSnappedIntRect to expand invalidation.

Source/core/layout/compositing/CompositedDeprecatedPaintLayerMapping.cpp

 /*
  * Copyright (C) 2009, 2010, 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 2021 matching lines @@
     IntRect r;
     PaintInvalidationReason invalidationReason;
 };
 
 // r is in the coordinate space of the layer's layout object
 void CompositedDeprecatedPaintLayerMapping::setContentsNeedDisplayInRect(const LayoutRect& r, PaintInvalidationReason invalidationReason)
 {
     // FIXME: need to split out paint invalidations for the background.
     // FIXME: need to distinguish invalidations for different layers (e.g. the main layer and scrolling layer). crbug.com/416535.
     SetContentsNeedsDisplayInRectFunctor functor = {
-        pixelSnappedIntRect(r.location() + m_owningLayer.subpixelAccumulation(), r.size()),
+        enclosingIntRect(LayoutRect(r.location() + m_owningLayer.subpixelAccumulation(), r.size())),
         invalidationReason
     };
     ApplyToGraphicsLayers(this, functor, ApplyToContentLayers);
 }
 
 void CompositedDeprecatedPaintLayerMapping::invalidateDisplayItemClient(const DisplayItemClientWrapper& displayItemClient)
 {
     ASSERT(RuntimeEnabledFeatures::slimmingPaintEnabled());
 
     // FIXME: need to split out paint invalidations for the background.
@@ skipping 344 matching lines @@
     } else if (graphicsLayer == m_scrollingBlockSelectionLayer.get()) {
         name = "Scrolling Block Selection Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace blink