Add CHECKs to ResourceLoader to investigate crashes

third_party/WebKit/Source/core/fetch/ResourceLoader.cpp

 /*
  * Copyright (C) 2006, 2007, 2010, 2011 Apple Inc. All rights reserved.
  *           (C) 2007 Graham Dennis (graham.dennis@gmail.com)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 49 matching lines @@
     : m_fetcher(fetcher),
       m_resource(resource),
       m_isCacheAwareLoadingActivated(false) {
   DCHECK(m_resource);
   DCHECK(m_fetcher);
 
   m_resource->setLoader(this);
 }
 
 ResourceLoader::~ResourceLoader() {
-  DCHECK(!m_loader);
+  CHECK(!m_loader);
 }
 
 DEFINE_TRACE(ResourceLoader) {
   visitor->trace(m_fetcher);
   visitor->trace(m_resource);
 }
 
 void ResourceLoader::start(const ResourceRequest& request) {
   DCHECK(!m_loader);
 
@@ skipping 214 matching lines @@
     }
     return ResourceRequestBlockedReason::Other;
   }
   return ResourceRequestBlockedReason::None;
 }
 
 void ResourceLoader::didReceiveResponse(
     const WebURLResponse& webURLResponse,
     std::unique_ptr<WebDataConsumerHandle> handle) {
   DCHECK(!webURLResponse.isNull());
+  CHECK(m_resource);
 
   const ResourceResponse& response = webURLResponse.toResourceResponse();
 
   if (response.wasFetchedViaServiceWorker()) {
     if (m_resource->options().corsEnabled == IsCORSEnabled &&
         response.wasFallbackRequiredByServiceWorker()) {
       ResourceRequest request = m_resource->lastResourceRequest();
       DCHECK_EQ(request.skipServiceWorker(),
                 WebURLRequest::SkipServiceWorker::None);
       // This code handles the case when a regular controlling service worker
@@ skipping 32 matching lines @@
   } else if (m_resource->options().corsEnabled == IsCORSEnabled) {
     ResourceRequestBlockedReason blockedReason =
         canAccessResponse(m_resource, response);
     if (blockedReason != ResourceRequestBlockedReason::None) {
       handleError(ResourceError::cancelledDueToAccessCheckError(response.url(),
                                                                 blockedReason));
       return;
     }
   }
 
+  CHECK(m_resource);
   context().dispatchDidReceiveResponse(
       m_resource->identifier(), response,
       m_resource->resourceRequest().frameType(),
       m_resource->resourceRequest().requestContext(), m_resource);
 
+  CHECK(m_resource);
   m_resource->responseReceived(response, std::move(handle));
   if (!m_resource->loader())
     return;
 
   if (response.httpStatusCode() >= 400 &&
       !m_resource->shouldIgnoreHTTPStatusCodeErrors())
     handleError(ResourceError::cancelledError(response.url()));
 }
 
 void ResourceLoader::didReceiveResponse(const WebURLResponse& response) {
@@ skipping 128 matching lines @@
     return;
 
   // Don't activate if cache policy is explicitly set.
   if (request.getCachePolicy() != WebCachePolicy::UseProtocolCachePolicy)
     return;
 
   m_isCacheAwareLoadingActivated = true;
 }
 
 }  // namespace blink