Restore KeyedServiceFactory diagnostics for context use-after-destroy.

chrome/browser/extensions/api/downloads/downloads_api_unittest.cc

Index: chrome/browser/extensions/api/downloads/downloads_api_unittest.cc
diff --git a/chrome/browser/extensions/api/downloads/downloads_api_unittest.cc b/chrome/browser/extensions/api/downloads/downloads_api_unittest.cc
index 1dfdc65b71ace841befe6ea2348ced65a41c9994..9082bdb3e066a3e9ce718b5d05b9dd09f1709f22 100644
--- a/chrome/browser/extensions/api/downloads/downloads_api_unittest.cc
+++ b/chrome/browser/extensions/api/downloads/downloads_api_unittest.cc
@@ -29,6 +29,12 @@ class TestDownloadService : public DownloadServiceImpl {
       : DownloadServiceImpl(profile), profile_(profile) {}
   ~TestDownloadService() override {}
 
+  void Shutdown() override {
+    DownloadServiceImpl::Shutdown();
+    download_history_.reset();
+    router_.reset();
+  }
+
   void set_download_history(std::unique_ptr<DownloadHistory> download_history) {
     download_history_.swap(download_history);
   }