Disallow adding ContextLifecycleObservers during iteration.

Source/platform/LifecycleObserver.h

 /*
  * 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 19 matching lines @@
 #include "platform/heap/Handle.h"
 #include "wtf/Assertions.h"
 
 namespace blink {
 
 template<typename T, typename Observer, typename Notifier>
 class LifecycleObserver : public WillBeGarbageCollectedMixin {
 public:
     using Context = T;
 
-    LifecycleObserver()
+    LifecycleObserver(Context* context)

[haraken, 2015/03/23 14:30:43]

Add explicit.

[sof, 2015/03/23 15:06:29]

Done, along with making the ctor protected.

         : m_lifecycleContext(nullptr)
     {
+        setContext(context);
     }
 
 #if !ENABLE(OILPAN)
     virtual ~LifecycleObserver()
     {
         dispose();
     }
 #endif
 
     DEFINE_INLINE_VIRTUAL_TRACE()
@@ skipping 25 matching lines @@
 
     m_lifecycleContext = context;
 
     if (m_lifecycleContext)
         static_cast<Notifier*>(m_lifecycleContext.get())->addObserver(static_cast<Observer*>(this));
 }
 
 } // namespace blink
 
 #endif // LifecycleObserver_h