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

/cc @electron/code-owners 
shell/browser/api/electron_api_app.h
#ifndef SHELL_BROWSER_API_ELECTRON_API_APP_H_
#define SHELL_BROWSER_API_ELECTRON_API_APP_H_
#include <memory>
#include <string>