Remove unused variable in ServiceWorkerNewScriptLoader unittest

A variable named test_loader_factory, declared in SetUp() of the
ServiceWorkerNewScriptLoaderTest is not used and therefore can be
removed.

Change-Id: I5d344dc6d29c5c473e62a76c6a1a005f3e6cc349
Reviewed-on: https://chromium-review.googlesource.com/1237693Reviewed-by: Makoto Shimazu <shimazu@chromium.org>
Commit-Queue: Momoko Hattori <momohatt@google.com>
Cr-Commit-Position: refs/heads/master@{#593804}

content/browser/service_worker/service_worker_new_script_loader_unittest.cc

@@ -173,7 +173,6 @@ class ServiceWorkerNewScriptLoaderTest : public testing::Test {
                 "this is an import script response body from the network")));
 
     // Initialize URLLoaderFactory.
-    network::mojom::URLLoaderFactoryPtr test_loader_factory;
     mock_url_loader_factory_ =
         std::make_unique<MockNetworkURLLoaderFactory>(mock_server_.get());
     helper_->SetNetworkFactory(mock_url_loader_factory_.get());