[NotLanded] Implement the fetching algorithm of the Web Manifest.

Source/core/testing/URLTestHelpers.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 35 matching lines @@
     registerMockedURLLoad(toKURL(fullString.c_str()), fileName, WebString::fromUTF8(""), mimeType);
 }
 
 void registerMockedURLLoad(const WebURL& fullURL, const WebString& fileName, const WebString& mimeType)
 {
     registerMockedURLLoad(fullURL, fileName, WebString::fromUTF8(""), mimeType);
 }
 
 void registerMockedURLLoad(const WebURL& fullURL, const WebString& fileName, const WebString& relativeBaseDirectory, const WebString& mimeType)
 {
-    WebURLResponse response;
-    response.initialize();
+    WebURLResponse response(fullURL);
     response.setMIMEType(mimeType);
     response.setHTTPStatusCode(200);
 
     // Physical file path for the mock = <webkitRootDir> + relativeBaseDirectory + fileName.
     std::string filePath = std::string(Platform::current()->unitTestSupport()->webKitRootDir().utf8().data());
     filePath.append("/Source/web/tests/data/");
     filePath.append(std::string(relativeBaseDirectory.utf8().data()));
     filePath.append(std::string(fileName.utf8().data()));
 
     Platform::current()->unitTestSupport()->registerMockedURL(fullURL, response, WebString::fromUTF8(filePath.c_str()));
 }
 
 } // namespace URLTestHelpers
 } // namespace blink