Add a release assert to validate that it's frame pointers which are missing.

third_party/WebKit/Source/core/paint/PaintLayer.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 886 matching lines @@
 
 // Return the enclosingCompositedLayerForPaintInvalidation for the given Layer
 // including crossing frame boundaries.
 PaintLayer* PaintLayer::enclosingLayerForPaintInvalidationCrossingFrameBoundaries() const
 {
     const PaintLayer* layer = this;
     PaintLayer* compositedLayer = 0;
     while (!compositedLayer) {
         compositedLayer = layer->enclosingLayerForPaintInvalidation();
         if (!compositedLayer) {
+            RELEASE_ASSERT(layer->layoutObject()->frame());
             LayoutObject* owner = layer->layoutObject()->frame()->ownerLayoutObject();
             if (!owner)
                 break;
             layer = owner->enclosingLayer();
         }
     }
     return compositedLayer;
 }
 
 PaintLayer* PaintLayer::enclosingLayerForPaintInvalidation() const
@@ skipping 1836 matching lines @@
 
 void showLayerTree(const blink::LayoutObject* layoutObject)
 {
     if (!layoutObject) {
         fprintf(stderr, "Cannot showLayerTree. Root is (nil)\n");
         return;
     }
     showLayerTree(layoutObject->enclosingLayer());
 }
 #endif