[XHR] Tidy up files for testing XHR's error for mixed content check failure

Source/core/loader/DocumentThreadableLoader.cpp

Index: Source/core/loader/DocumentThreadableLoader.cpp
diff --git a/Source/core/loader/DocumentThreadableLoader.cpp b/Source/core/loader/DocumentThreadableLoader.cpp
index 8b84b7147cada891d7ace3393be6bb007a543489..201caff37149165d92efdb0abf7e586df872a6cd 100644
--- a/Source/core/loader/DocumentThreadableLoader.cpp
+++ b/Source/core/loader/DocumentThreadableLoader.cpp
@@ -593,11 +593,18 @@ void DocumentThreadableLoader::loadRequest(const ResourceRequest& request, Resou
         if (m_options.crossOriginRequestPolicy == AllowCrossOriginRequests)
             newRequest.setOriginRestriction(FetchRequest::NoOriginRestriction);
         ASSERT(!resource());
+
         if (request.requestContext() == WebURLRequest::RequestContextVideo || request.requestContext() == WebURLRequest::RequestContextAudio)
             setResource(RawResource::fetchMedia(newRequest, m_document.fetcher()));
         else
             setResource(RawResource::fetch(newRequest, m_document.fetcher()));
-        if (resource() && resource()->loader()) {
+
+        if (!resource()) {
+            m_client->didFail(ResourceError(errorDomainBlinkInternal, 0, requestURL.string(), "Failed to start loading."));
+            return;
+        }
+
+        if (resource()->loader()) {
             unsigned long identifier = resource()->identifier();
             InspectorInstrumentation::documentThreadableLoaderStartedLoadingForClient(&m_document, identifier, m_client);
         }