It's going to be removed from Chromium, see https://crbug.com/812523.

/cc @electron/code-owners 
shell/browser/api/electron_api_app.h
#endif
namespace api {
class App : public ElectronBrowserClient::Delegate,
            public gin_helper::EventEmitter<App>,
            public BrowserObserver,
            public content::GpuDataManagerObserver,
            public content::BrowserChildProcessObserver {
 public:
  using FileIconCallback =
      base::RepeatingCallback<void(v8::Local<v8::Value>, const gfx::Image&)>;
  static gin::Handle<App> Create(v8::Isolate* isolate);
  static void BuildPrototype(v8::Isolate* isolate,
                             v8::Local<v8::FunctionTemplate> prototype);
#if defined(USE_NSS_CERTS)
  void OnCertificateManagerModelCreated(
      std::unique_ptr<base::DictionaryValue> options,
      net::CompletionOnceCallback callback,
      std::unique_ptr<CertificateManagerModel> model);
#endif
  base::FilePath GetAppPath() const;
  void RenderProcessReady(content::RenderProcessHost* host);
  void RenderProcessDisconnected(base::ProcessId host_pid);
  void PreMainMessageLoopRun();
 protected:
  explicit App(v8::Isolate* isolate);
  ~App() override;