Make WebURLLoaderMockFactoryImpl::createURLLoader accept nullptr

third_party/WebKit/Source/platform/testing/WebURLLoaderMockFactoryImpl.cpp

 // Copyright 2016 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 "platform/testing/WebURLLoaderMockFactoryImpl.h"
 
 #include "base/files/file_util.h"
 #include "base/run_loop.h"
 #include "platform/testing/TestingPlatformSupport.h"
 #include "platform/testing/UnitTestHelpers.h"
@@ skipping 14 matching lines @@
 }
 
 WebURLLoaderMockFactoryImpl::WebURLLoaderMockFactoryImpl(
     TestingPlatformSupport* platform)
     : m_platform(platform) {}
 
 WebURLLoaderMockFactoryImpl::~WebURLLoaderMockFactoryImpl() {}
 
 WebURLLoader* WebURLLoaderMockFactoryImpl::createURLLoader(
     WebURLLoader* defaultLoader) {
-  DCHECK(defaultLoader);
   return new WebURLLoaderMock(this, defaultLoader);
 }
 
 void WebURLLoaderMockFactoryImpl::registerURL(const WebURL& url,
                                               const WebURLResponse& response,
                                               const WebString& filePath) {
   ResponseInfo responseInfo;
   responseInfo.response = response;
   if (!filePath.isNull() && !filePath.isEmpty()) {
     responseInfo.filePath = blink::WebStringToFilePath(filePath);
@@ skipping 127 matching lines @@
 
   std::string buffer;
   if (!base::ReadFileToString(filePath, &buffer))
     return false;
 
   data->assign(buffer.data(), buffer.size());
   return true;
 }
 
 }  // namespace blink