Disable paint invalidation state assert in invalidateScrollCornerRect()

Source/core/paint/DeprecatedPaintLayerScrollableArea.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 233 matching lines @@
         // invalidate the rectangles to trigger repaints.
         box().invalidatePaintRectangleNotInvalidatingDisplayItemClients(LayoutRect(intRect));
     }
 }
 
 void DeprecatedPaintLayerScrollableArea::invalidateScrollCornerRect(const IntRect& rect)
 {
     ASSERT(!layerForScrollCorner());
 
     if (m_scrollCorner) {
+        // FIXME: We should not allow paint invalidation out of paint invalidation state. crbug.com/457415
+        DisablePaintInvalidationStateAsserts disabler;
         m_scrollCorner->invalidatePaintRectangle(LayoutRect(rect));
         if (RuntimeEnabledFeatures::slimmingPaintEnabled())
             box().invalidateDisplayItemClientForNonCompositingDescendantsOf(*m_scrollCorner);
     } else if (RuntimeEnabledFeatures::slimmingPaintEnabled()) {
         box().invalidateDisplayItemClient(box());
     }
     if (m_resizer) {
         m_resizer->invalidatePaintRectangle(LayoutRect(rect));
         if (RuntimeEnabledFeatures::slimmingPaintEnabled())
             box().invalidateDisplayItemClientForNonCompositingDescendantsOf(*m_resizer);
@@ skipping 1236 matching lines @@
         return false;
 
     LocalFrame* frame = box().frame();
     if (!frame || !frame->isMainFrame() || !frame->settings())
         return false;
 
     return frame->settings()->viewportMetaEnabled();
 }
 
 } // namespace blink