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

Source/core/layout/LayoutBoxModelObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 232 matching lines @@
 
     if (!shouldCheckForPaintInvalidation(paintInvalidationState))
         return;
 
     bool establishesNewPaintInvalidationContainer = isPaintInvalidationContainer();
     const LayoutBoxModelObject& newPaintInvalidationContainer = *adjustCompositedContainerForSpecialAncestors(establishesNewPaintInvalidationContainer ? this : &paintInvalidationState.paintInvalidationContainer());
     // FIXME: This assert should be re-enabled when we move paint invalidation to after compositing update. crbug.com/360286
     // ASSERT(&newPaintInvalidationContainer == containerForPaintInvalidation());
 
     PaintInvalidationReason reason = invalidatePaintIfNeeded(paintInvalidationState, newPaintInvalidationContainer);
-    clearPaintInvalidationState(paintInvalidationState);
+    if (reason != PaintInvalidationDelayedFull) {
+        clearPaintInvalidationState(paintInvalidationState);
+    } else {
+        // Mark this object as needing paint invalidation again in the next frame, due to the request for delayed paint invalidation.
+        setShouldDoFullPaintInvalidation();
+    }
 
     PaintInvalidationState childTreeWalkState(paintInvalidationState, *this, newPaintInvalidationContainer);
     if (reason == PaintInvalidationLocationChange)
         childTreeWalkState.setForceCheckForPaintInvalidation();
     invalidatePaintOfSubtreesIfNeeded(childTreeWalkState);
 }
 
 void LayoutBoxModelObject::setBackingNeedsPaintInvalidationInRect(const LayoutRect& r, PaintInvalidationReason invalidationReason) const
 {
     // https://bugs.webkit.org/show_bug.cgi?id=61159 describes an unreproducible crash here,
@@ skipping 598 matching lines @@
     ASSERT(!beforeChild || toBoxModelObject == beforeChild->parent());
     for (LayoutObject* child = startChild; child && child != endChild; ) {
         // Save our next sibling as moveChildTo will clear it.
         LayoutObject* nextSibling = child->nextSibling();
         moveChildTo(toBoxModelObject, child, beforeChild, fullRemoveInsert);
         child = nextSibling;
     }
 }
 
 } // namespace blink