[ES6 modules] Introduce Modulator "module map settings object"

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

+// Copyright 2017 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.
+
+#include "core/dom/Modulator.h"
+
+#include "bindings/core/v8/ScriptState.h"
+
+namespace blink {
+
+Modulator* Modulator::from(LocalFrame* frame) {
+  ScriptState* scriptState = ScriptState::forMainWorld(frame);
+  if (!scriptState)
+    return nullptr;
+  // TODO(kouhei): setModulator in V8PerContextData when we land ModulatorImpl.
+  return scriptState->perContextData()->modulator();
+}
+
+}  // namespace blink