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

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

Index: third_party/WebKit/Source/core/dom/IdTargetObserverRegistry.cpp
diff --git a/third_party/WebKit/Source/core/dom/IdTargetObserverRegistry.cpp b/third_party/WebKit/Source/core/dom/IdTargetObserverRegistry.cpp
index fedf7a7917567b57c67397fc7d47e19201a903fe..57af0c7a1c491d5411698978bf2d9c87269aa05e 100644
--- a/third_party/WebKit/Source/core/dom/IdTargetObserverRegistry.cpp
+++ b/third_party/WebKit/Source/core/dom/IdTargetObserverRegistry.cpp
@@ -67,7 +67,7 @@ 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;
 
@@ -87,7 +87,7 @@ void IdTargetObserverRegistry::notifyObserversInternal(const AtomicString& id) {
 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();
 }