Replace ASSERT family with DCHECK and so on in core/dom/.

third_party/WebKit/Source/core/dom/custom/V0CustomElementObserver.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 35 matching lines @@
 
 void V0CustomElementObserver::notifyElementWasDestroyed(Element* element) {
   ElementObserverMap::iterator it = elementObservers().find(element);
   if (it == elementObservers().end())
     return;
   it->value->elementWasDestroyed(element);
 }
 
 void V0CustomElementObserver::observe(Element* element) {
   ElementObserverMap::AddResult result = elementObservers().add(element, this);
-  ASSERT_UNUSED(result, result.isNewEntry);
+  DCHECK(result.isNewEntry);
 }
 
 void V0CustomElementObserver::unobserve(Element* element) {
   V0CustomElementObserver* observer = elementObservers().take(element);
-  ASSERT_UNUSED(observer, observer == this);
+  DCHECK_EQ(observer, this);
 }
 
 }  // namespace blink