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

Source/platform/graphics/PaintInvalidationReason.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef PaintInvalidationReason_h
 #define PaintInvalidationReason_h
 
 #include "platform/PlatformExport.h"
 
 namespace blink {
 
 enum PaintInvalidationReason {
     PaintInvalidationNone,
     PaintInvalidationIncremental,
     PaintInvalidationRectangle,
     // The following reasons will all cause full invalidation of the LayoutObject.
     PaintInvalidationFull, // Any unspecified reason of full invalidation.
     PaintInvalidationStyleChange,
     PaintInvalidationForcedByLayout,
     PaintInvalidationCompositingUpdate,
     PaintInvalidationBorderBoxChange,
     PaintInvalidationBoundsChange,
     PaintInvalidationLocationChange,
     PaintInvalidationBecameVisible,
     PaintInvalidationBecameInvisible,
     PaintInvalidationScroll,
     PaintInvalidationSelection,
     PaintInvalidationLayer,
     PaintInvalidationRendererInsertion,
-    PaintInvalidationRendererRemoval
+    PaintInvalidationRendererRemoval,
+    // PaintInvalidationDelayedFull means that PaintInvalidationFull is needed in order to fully paint
+    // the content, but that painting of the object can be delayed until a future frame.
+    // This can be the case for an object whose content is not visible to the user.
+    PaintInvalidationDelayedFull
 };
 
 PLATFORM_EXPORT const char* paintInvalidationReasonToString(PaintInvalidationReason);
 
 inline bool isFullPaintInvalidationReason(PaintInvalidationReason reason)
 {
     return reason >= PaintInvalidationFull;
 }
 
 } // namespace blink
 
 #endif // PaintInvalidationReason_h