Add support for GetAuthCredentials (fixes issue #2718, see issue #2622).

When NetworkService is enabled requests created using CefFrame::CreateURLRequest
will call CefRequestHandler::GetAuthCredentials for the associated browser after
calling CefURLRequestClient::GetAuthCredentials if that call returns false.

patch/patch.cfg

@@ -418,6 +418,14 @@ patches = [
     # https://bitbucket.org/chromiumembedded/cef/issues/2622
     'name': 'services_network_2622',
   },
+  {
+    # Enhancements to NetworkService:
+    # - Support customization of request_id via SimpleURLLoader.
+    # - Remove the non-nullptr WebContents requirement from
+    #   NetworkServiceClient::OnAuthRequired.
+    # https://bitbucket.org/chromiumembedded/cef/issues/2718
+    'name': 'services_network_request_id_2718',
+  },
   {
     # Windows: Remove the base::Value is_standard_layout assert which will fail
     # for the cef_sandbox build, and which is no longer required.