[bindings] Migrate V8TestingScope out of V8Binding.h/cpp

Source/bindings/core/v8/V8TestingScope.cpp

+// Copyright (c) 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.
+
+#include "config.h"
+#include "bindings/core/v8/V8TestingScope.h"
+
+#include "bindings/core/v8/DOMWrapperWorld.h"
+
+namespace blink {
+
+V8TestingScope::V8TestingScope(v8::Isolate* isolate)
+    : m_handleScope(isolate)
+    , m_contextScope(v8::Context::New(isolate))
+    // We reuse the main world since the main world is guaranteed to be registered to ScriptController.
+    , m_scriptState(ScriptStateForTesting::create(isolate->GetCurrentContext(), &DOMWrapperWorld::mainWorld()))
+{
+}
+
+V8TestingScope::~V8TestingScope()
+{
+    m_scriptState->disposePerContextData();
+}
+
+ScriptState* V8TestingScope::scriptState() const
+{
+    return m_scriptState.get();
+}
+
+v8::Isolate* V8TestingScope::isolate() const
+{
+    return m_scriptState->isolate();
+}
+
+} // namespace blink