mv FetchTestingPlatformSupport to platform/loader/testing

third_party/WebKit/Source/platform/loader/fetch/FetchTestingPlatformSupport.h

-// 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.
-
-#ifndef FetchTestingPlatformSupport_h
-#define FetchTestingPlatformSupport_h
-
-#include "platform/heap/Persistent.h"
-#include "platform/testing/TestingPlatformSupport.h"
-#include <memory>
-
-namespace blink {
-
-class MockFetchContext;
-
-class FetchTestingPlatformSupport
-    : public TestingPlatformSupportWithMockScheduler {
- public:
-  FetchTestingPlatformSupport();
-  ~FetchTestingPlatformSupport() override;
-
-  MockFetchContext* context();
-
-  // Platform:
-  WebURLError cancelledError(const WebURL&) const override;
-  WebURLLoaderMockFactory* getURLLoaderMockFactory() override;
-  WebURLLoader* createURLLoader() override;
-
- private:
-  class FetchTestingWebURLLoaderMockFactory;
-
-  Persistent<MockFetchContext> m_context;
-  std::unique_ptr<WebURLLoaderMockFactory> m_urlLoaderMockFactory;
-
-  DISALLOW_COPY_AND_ASSIGN(FetchTestingPlatformSupport);
-};
-
-}  // namespace blink
-
-#endif