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

third_party/WebKit/Source/core/html/HTMLCollection.h

Index: third_party/WebKit/Source/core/html/HTMLCollection.h
diff --git a/third_party/WebKit/Source/core/html/HTMLCollection.h b/third_party/WebKit/Source/core/html/HTMLCollection.h
index dd02557cd429bebc397d7aeaa04000dba395cb45..474332fd1720964f0572f7ca3fc655889e64c870 100644
--- a/third_party/WebKit/Source/core/html/HTMLCollection.h
+++ b/third_party/WebKit/Source/core/html/HTMLCollection.h
@@ -123,11 +123,11 @@ class CORE_EXPORT HTMLCollection
     static NamedItemCache* create() { return new NamedItemCache; }
 
     HeapVector<Member<Element>>* getElementsById(const AtomicString& id) const {
-      return m_idCache.get(id.impl());
+      return m_idCache.at(id.impl());
     }
     HeapVector<Member<Element>>* getElementsByName(
         const AtomicString& name) const {
-      return m_nameCache.get(name.impl());
+      return m_nameCache.at(name.impl());
     }
     void addElementWithId(const AtomicString& id, Element* element) {
       addElementToMap(m_idCache, id, element);