[S.P.] Don't draw frames of animated images that are offscreen

Source/core/layout/LayoutHTMLCanvas.cpp

 /*
  * Copyright (C) 2004, 2006, 2007 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 63 matching lines @@
     LayoutSize oldSize = size();
     updateLogicalWidth();
     updateLogicalHeight();
     if (oldSize == size())
         return;
 
     if (!selfNeedsLayout())
         setNeedsLayout();
 }
 
-PaintInvalidationReason LayoutHTMLCanvas::invalidatePaintIfNeeded(const PaintInvalidationState& paintInvalidationState, const LayoutBoxModelObject& paintInvalidationContainer)
+PaintInvalidationReason LayoutHTMLCanvas::invalidatePaintIfNeeded(PaintInvalidationState& paintInvalidationState, const LayoutBoxModelObject& paintInvalidationContainer)
 {
     PaintInvalidationReason reason = LayoutBox::invalidatePaintIfNeeded(paintInvalidationState, paintInvalidationContainer);
     HTMLCanvasElement* element = toHTMLCanvasElement(node());
     if (element->isDirty()) {
         element->doDeferredPaintInvalidation();
         if (reason < PaintInvalidationRectangle)
             reason = PaintInvalidationRectangle;
     }
     return reason;
 }
 
 CompositingReasons LayoutHTMLCanvas::additionalCompositingReasons() const
 {
     if (toHTMLCanvasElement(node())->shouldBeDirectComposited())
         return CompositingReasonCanvas;
     return CompositingReasonNone;
 }
 
 } // namespace blink