V8ObjectBuilder::addString support Nullable.

third_party/WebKit/Source/bindings/core/v8/V8ObjectBuilder.h

 // 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.
 
 #ifndef V8ObjectBuilder_h
 #define V8ObjectBuilder_h
 
 #include "bindings/core/v8/ToV8.h"
 #include "core/CoreExport.h"
 #include "platform/heap/Handle.h"
 #include "wtf/text/WTFString.h"
 #include <v8.h>
 
 namespace blink {
 
 class ScriptState;
 class ScriptValue;
 
 class CORE_EXPORT V8ObjectBuilder final {
   STACK_ALLOCATED();
 
  public:
   explicit V8ObjectBuilder(ScriptState*);
 
   ScriptState* getScriptState() const { return m_scriptState.get(); }
 
-  V8ObjectBuilder& add(const String& name, const V8ObjectBuilder&);
+  V8ObjectBuilder& add(const StringView& name, const V8ObjectBuilder&);
 
-  V8ObjectBuilder& addNull(const String& name);
-  V8ObjectBuilder& addBoolean(const String& name, bool value);
-  V8ObjectBuilder& addNumber(const String& name, double value);
-  V8ObjectBuilder& addString(const String& name, const String& value);
+  V8ObjectBuilder& addNull(const StringView& name);
+  V8ObjectBuilder& addBoolean(const StringView& name, bool value);
+  V8ObjectBuilder& addNumber(const StringView& name, double value);
+  V8ObjectBuilder& addString(const StringView& name, const StringView& value);
+  V8ObjectBuilder& addStringOrNull(const StringView& name,
+                                   const StringView& value);
 
   template <typename T>
-  V8ObjectBuilder& add(const String& name, const T& value) {
+  V8ObjectBuilder& add(const StringView& name, const T& value) {
     addInternal(name, v8::Local<v8::Value>(
                           toV8(value, m_scriptState->context()->Global(),
                                m_scriptState->isolate())));
     return *this;
   }
 
   ScriptValue scriptValue() const;
   v8::Local<v8::Object> v8Value() const { return m_object; }
 
  private:
-  void addInternal(const String& name, v8::Local<v8::Value>);
+  void addInternal(const StringView& name, v8::Local<v8::Value>);
 
   RefPtr<ScriptState> m_scriptState;
   v8::Local<v8::Object> m_object;
 };
 
 }  // namespace blink
 
 #endif  // V8ObjectBuilder_h