Add download_to_file DCHECKs to a bunch of URLLoaderFactories.

These factories don't support download_to_file anyway, so make sure
nobody is trying to call them with download_to_file set to true.

Also fix the one place where download_to_file was set to true despite
the code not actually expecting the callbacks that that should result
in, if download_to_file would have been implemented.

Bug: 791702
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_mojo
Change-Id: I2f31d2a45c59ba4b15e92cfe18718ed4eb69847b
Reviewed-on: https://chromium-review.googlesource.com/957708Reviewed-by: Min Qin <qinmin@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: Marijn Kruisselbrink <mek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#542869}

content/browser/blob_storage/blob_url_loader_factory.cc

@@ -71,6 +71,7 @@ void BlobURLLoaderFactory::CreateLoaderAndStart(
     const network::ResourceRequest& request,
     network::mojom::URLLoaderClientPtr client,
     const net::MutableNetworkTrafficAnnotationTag& traffic_annotation) {
+  DCHECK(!request.download_to_file);
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   std::unique_ptr<storage::BlobDataHandle> blob_handle;
   if (blob_storage_context_) {

content/browser/download/download_utils.cc

@@ -142,7 +142,6 @@ std::unique_ptr<network::ResourceRequest> CreateResourceRequest(
   request->site_for_cookies = params->url();
   request->referrer = params->referrer();
   request->referrer_policy = params->referrer_policy();
-  request->download_to_file = true;
   request->allow_download = true;
   request->is_main_frame = true;
 

content/browser/file_url_loader_factory.cc

@@ -630,6 +630,7 @@ void FileURLLoaderFactory::CreateLoaderAndStart(
     const network::ResourceRequest& request,
     network::mojom::URLLoaderClientPtr client,
     const net::MutableNetworkTrafficAnnotationTag& traffic_annotation) {
+  DCHECK(!request.download_to_file);
   base::FilePath file_path;
   const bool is_file = net::FileURLToFilePath(request.url, &file_path);
   if (is_file && file_path.EndsWithSeparator() && file_path.IsAbsolute()) {

content/browser/webui/web_ui_url_loader_factory.cc

@@ -243,6 +243,7 @@ class WebUIURLLoaderFactory : public network::mojom::URLLoaderFactory,
                             const net::MutableNetworkTrafficAnnotationTag&
                                 traffic_annotation) override {
     DCHECK_CURRENTLY_ON(BrowserThread::UI);
+    DCHECK(!request.download_to_file);
 
     if (request.url.scheme() != scheme_) {
       DVLOG(1) << "Bad scheme: " << request.url.scheme();

extensions/browser/extension_protocols.cc

@@ -765,6 +765,7 @@ class ExtensionURLLoaderFactory : public network::mojom::URLLoaderFactory {
                             const net::MutableNetworkTrafficAnnotationTag&
                                 traffic_annotation) override {
     DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+    DCHECK(!request.download_to_file);
     const content::RenderProcessHost* process_host = frame_host_->GetProcess();
     BrowserContext* browser_context = process_host->GetBrowserContext();
 

services/network/public/cpp/resource_request.h

@@ -148,6 +148,8 @@ struct COMPONENT_EXPORT(NETWORK_CPP_BASE) ResourceRequest {
 
   // If true, then the response body will be downloaded to a file and the path
   // to that file will be provided in ResponseInfo::download_file_path.
+  // Deprecated and not supported by the network service code.
+  // TODO(mek): Remove this flag once all usage of it is gone (XHR and PPAPI).
   bool download_to_file = false;
 
   // True if the request can work after the fetch group is terminated.

services/network/url_loader_factory.cc

@@ -41,6 +41,7 @@ void URLLoaderFactory::CreateLoaderAndStart(
     const ResourceRequest& url_request,
     mojom::URLLoaderClientPtr client,
     const net::MutableNetworkTrafficAnnotationTag& traffic_annotation) {
+  DCHECK(!url_request.download_to_file);
   bool report_raw_headers = false;
   if (url_request.report_raw_headers) {
     const NetworkService* service = context_->network_service();

storage/browser/blob/blob_url_loader_factory.cc

@@ -29,6 +29,7 @@ void BlobURLLoaderFactory::CreateLoaderAndStart(
     bindings_.ReportBadMessage("Invalid URL when attempting to fetch Blob");
     return;
   }
+  DCHECK(!request.download_to_file);
   BlobURLLoader::CreateAndStart(
       std::move(loader), request, std::move(client),
       handle_ ? std::make_unique<BlobDataHandle>(*handle_) : nullptr);