[bindings] Refactor ScriptStateForTesting, V8TestingScope into V8BindingForTesting.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