Enable download page action for error page

components/error_page/renderer/net_error_helper_core_unittest.cc

Index: components/error_page/renderer/net_error_helper_core_unittest.cc
diff --git a/components/error_page/renderer/net_error_helper_core_unittest.cc b/components/error_page/renderer/net_error_helper_core_unittest.cc
index 79d84d686912cfb9c6f818bd727def497974a473..db07d6862e249174ef67ef17085a345f89502552 100644
--- a/components/error_page/renderer/net_error_helper_core_unittest.cc
+++ b/components/error_page/renderer/net_error_helper_core_unittest.cc
@@ -435,6 +435,8 @@ class NetErrorHelperCoreTest : public testing::Test,
     download_count_++;
   }
 
+  void SetIsShowingDownloadButton(bool show) override {}
+
   void SendTrackingRequest(const GURL& tracking_url,
                            const std::string& tracking_request_body) override {
     last_tracking_url_ = tracking_url;