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

Source/core/layout/LayoutObject.h

Index: Source/core/layout/LayoutObject.h
diff --git a/Source/core/layout/LayoutObject.h b/Source/core/layout/LayoutObject.h
index 89bc6dcc4e991f9e3f987381e63c16546707dc03..0dca8f69d349ac1080c8d1fe661a0245ffa6500b 100644
--- a/Source/core/layout/LayoutObject.h
+++ b/Source/core/layout/LayoutObject.h
@@ -250,6 +250,8 @@ public:
 
     void assertSubtreeClearedPaintInvalidationState() const
     {
+        if (RuntimeEnabledFeatures::slimmingPaintEnabled())

[esprehn, 2015/03/25 05:06:36]

This means bugs can sneak in, if you use a separate vector you can leave the
assert which is good.

+            return;
         for (const LayoutObject* renderer = this; renderer; renderer = renderer->nextInPreOrder())
             renderer->assertRendererClearedPaintInvalidationState();
     }