Tidy up ActiveDOMObject destructor.

Source/core/dom/ActiveDOMObject.cpp

 /*
  * Copyright (C) 2008 Apple 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 33 matching lines @@
     // let's count objects on other threads as many as possible.
     if (isMainThread())
         InstanceCounters::incrementCounter(InstanceCounters::ActiveDOMObjectCounter);
 }
 
 ActiveDOMObject::~ActiveDOMObject()
 {
     if (isMainThread())
         InstanceCounters::decrementCounter(InstanceCounters::ActiveDOMObjectCounter);
 
-    // ActiveDOMObject may be inherited by a sub-class whose life-cycle
-    // exceeds that of the associated ExecutionContext. In those cases,
-    // m_executionContext would/should have been nullified by
-    // ContextLifecycleObserver::contextDestroyed() (which we implement /
-    // inherit). Hence, we should ensure that this is not 0 before use it
-    // here.
-    if (!executionContext())
-        return;
+    ASSERT(m_suspendIfNeededCalled);
 
-    ASSERT(m_suspendIfNeededCalled);
+    // Oilpan: not valid to access executionContext() in the destructor.
 #if !ENABLE(OILPAN)
-    ASSERT(executionContext()->isContextThread());
+    ASSERT(!executionContext() || executionContext()->isContextThread());
 #endif
 }
 
 void ActiveDOMObject::suspendIfNeeded()
 {
 #if ENABLE(ASSERT)
     ASSERT(!m_suspendIfNeededCalled);
     m_suspendIfNeededCalled = true;
 #endif
     if (ExecutionContext* context = executionContext())
@@ skipping 28 matching lines @@
 
     if (context->activeDOMObjectsAreSuspended()) {
         suspend();
         return;
     }
 
     resume();
 }
 
 } // namespace blink