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

third_party/WebKit/Source/core/style/StyleNonInheritedVariables.h

 // Copyright 2016 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.
 
 #ifndef StyleNonInheritedVariables_h
 #define StyleNonInheritedVariables_h
 
 #include "core/css/CSSValue.h"
 #include "core/css/CSSVariableData.h"
 #include "wtf/Forward.h"
@@ skipping 19 matching lines @@
 
   void setVariable(const AtomicString& name,
                    PassRefPtr<CSSVariableData> value) {
     m_data.set(name, std::move(value));
   }
   CSSVariableData* getVariable(const AtomicString& name) const;
   void removeVariable(const AtomicString&);
 
   void setRegisteredVariable(const AtomicString&, const CSSValue*);
   const CSSValue* registeredVariable(const AtomicString& name) const {
-    return m_registeredData.get(name);
+    return m_registeredData.at(name);
   }
 
  private:
   StyleNonInheritedVariables() = default;
   StyleNonInheritedVariables(StyleNonInheritedVariables&);
 
   friend class CSSVariableResolver;
 
   HashMap<AtomicString, RefPtr<CSSVariableData>> m_data;
   HashMap<AtomicString, Persistent<CSSValue>> m_registeredData;
 };
 
 }  // namespace blink
 
 #endif  // StyleNonInheritedVariables_h