[Slimming Paint] Track clip renderers

Source/core/paint/ViewDisplayList.cpp

 // 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.
 
 #include "config.h"
 #include "core/paint/ViewDisplayList.h"
 
 #include "platform/NotImplemented.h"
 #include "platform/RuntimeEnabledFeatures.h"
 
@@ skipping 33 matching lines @@
     PaintList::iterator end = m_paintList.end();
     if (displayItem.renderer() && !m_paintListRenderers.contains(displayItem.renderer()))
         return end;
 
     for (PaintList::iterator it = begin; it != end; ++it) {
         DisplayItem& existing = **it;
         if (existing.idsEqual(displayItem))
             return it;
     }
 
-    // FIXME: Properly handle clips.
-    ASSERT(!displayItem.renderer());
+    ASSERT_NOT_REACHED();
     return end;
 }
 
 bool ViewDisplayList::wasInvalidated(const DisplayItem& displayItem) const
 {
     // FIXME: Use a bit on RenderObject instead of tracking m_invalidated.
     return displayItem.renderer() && m_invalidated.contains(displayItem.renderer());
 }
 
 static void appendDisplayItem(PaintList& list, HashSet<const RenderObject*>& renderers, WTF::PassOwnPtr<DisplayItem> displayItem)
@@ skipping 112 matching lines @@
 }
 
 void ViewDisplayList::showDebugData() const
 {
     fprintf(stderr, "paint list: [%s]\n", paintListAsDebugString(m_paintList).utf8().data());
     fprintf(stderr, "new paints: [%s]\n", paintListAsDebugString(m_newPaints).utf8().data());
 }
 #endif
 
 } // namespace blink