Split up ios/web:test_support.

ios/web/public/test/response_providers/string_response_provider.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 IOS_WEB_PUBLIC_TEST_RESPONSE_PROVIDERS_STRING_RESPONSE_PROVIDER_H_
-#define IOS_WEB_PUBLIC_TEST_RESPONSE_PROVIDERS_STRING_RESPONSE_PROVIDER_H_
-
-#include <string>
-
-#include "base/macros.h"
-#import "ios/web/public/test/response_providers/data_response_provider.h"
-
-namespace web {
-
-// A response provider that returns a  string for all requests. Used for testing
-// purposes.
-class StringResponseProvider : public web::DataResponseProvider {
- public:
-  explicit StringResponseProvider(const std::string& response_body);
-
-  // web::DataResponseProvider methods.
-  bool CanHandleRequest(const Request& request) override;
-  void GetResponseHeadersAndBody(
-      const Request& request,
-      scoped_refptr<net::HttpResponseHeaders>* headers,
-      std::string* response_body) override;
-
- private:
-  // The string that is returned in the response body.
-  std::string response_body_;
-  DISALLOW_COPY_AND_ASSIGN(StringResponseProvider);
-};
-
-}  // namespace web
-
-#endif  // IOS_WEB_PUBLIC_TEST_RESPONSE_PROVIDERS_STRING_RESPONSE_PROVIDER_H_