Start removing the double-negative !ASSERT_DISABLED

Source/core/dom/DocumentLifecycle.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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 53 matching lines @@
 DocumentLifecycle::DocumentLifecycle()
     : m_state(Uninitialized)
     , m_detachCount(0)
 {
 }
 
 DocumentLifecycle::~DocumentLifecycle()
 {
 }
 
-#if !ASSERT_DISABLED
+#if ASSERT_ENABLED
 
 bool DocumentLifecycle::canAdvanceTo(State state) const
 {
     if (state > m_state)
         return true;
     if (m_state == Disposed) {
         // FIXME: We can dispose a document multiple times. This seems wrong.
         // See https://code.google.com/p/chromium/issues/detail?id=301668.
         return state == Disposed;
     }
@@ skipping 73 matching lines @@
 void DocumentLifecycle::ensureStateAtMost(State state)
 {
     ASSERT(state == VisualUpdatePending || state == StyleClean || state == LayoutClean);
     if (m_state <= state)
         return;
     ASSERT(canRewindTo(state));
     m_state = state;
 }
 
 }