Fix include guards of files in src/ios.

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_
-#define IOS_WEB_PUBLIC_TEST_RESPONSE_PROVIDERS_STRING_RESPONSE_PROVIDER_
+#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"
 #include "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_
+#endif  // IOS_WEB_PUBLIC_TEST_RESPONSE_PROVIDERS_STRING_RESPONSE_PROVIDER_H_