Avoid snapshotting ContextLifecycleObservers when iterating.

third_party/WebKit/Source/core/frame/LocalFrameLifecycleNotifier.cpp

 // Copyright 2015 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 "core/frame/LocalFrameLifecycleNotifier.h"
 
 #include "core/frame/LocalFrameLifecycleObserver.h"
 
 namespace blink {
 
 void LocalFrameLifecycleNotifier::notifyWillDetachFrameHost()
 {
-    TemporaryChange<IterationType> scope(m_iterating, IteratingOverAll);
+    TemporaryChange<IterationState> scope(m_iterationState, AllowingNone);
     for (LocalFrameLifecycleObserver* observer : m_observers)
         observer->willDetachFrameHost();
 }
 
 } // namespace blink