Migrate WTF::HashMap::get() to ::at()

third_party/WebKit/Source/core/dom/IdTargetObserverRegistry.cpp

 /*
  * Copyright (C) 2012 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 49 matching lines @@
   ObserverSet* set = iter->value.get();
   set->erase(observer);
   if (set->isEmpty() && set != m_notifyingObserversInSet)
     m_registry.remove(iter);
 }
 
 void IdTargetObserverRegistry::notifyObserversInternal(const AtomicString& id) {
   DCHECK(!id.isEmpty());
   DCHECK(!m_registry.isEmpty());
 
-  m_notifyingObserversInSet = m_registry.get(id.impl());
+  m_notifyingObserversInSet = m_registry.at(id.impl());
   if (!m_notifyingObserversInSet)
     return;
 
   HeapVector<Member<IdTargetObserver>> copy;
   copyToVector(*m_notifyingObserversInSet, copy);
   for (const auto& observer : copy) {
     if (m_notifyingObserversInSet->contains(observer))
       observer->idTargetChanged();
   }
 
   if (m_notifyingObserversInSet->isEmpty())
     m_registry.erase(id.impl());
 
   m_notifyingObserversInSet = nullptr;
 }
 
 bool IdTargetObserverRegistry::hasObservers(const AtomicString& id) const {
   if (id.isEmpty() || m_registry.isEmpty())
     return false;
-  ObserverSet* set = m_registry.get(id.impl());
+  ObserverSet* set = m_registry.at(id.impl());
   return set && !set->isEmpty();
 }
 
 }  // namespace blink