* Output of `node_modules/.bin/electron --version`: v4.0.0
* Operating System (Platform and Version): macOS 10.14.2

* Output of `node_modules/.bin/electron --version` on last known working Electron version (if applicable): 2.0.7

### Expected behavior

I should be able to call `app.setAccessibilitySupportEnabled(true)` during initialization, and the application should start and stay open.

### Actual behavior

The application starts and exits immediately if `app.setAccessibilitySupportEnabled(true)` is called during initialization. Same for passing in `false`.

### How to reproduce

Here is a simple project that shows this error. The application behaves as expected (does not exit immediately) when this line is commented out:
https://github.com/marisademeglio/electron4-setA11yTreeEnabled/blob/master/src/main/main.js#L27

  $ git clone https://github.com/marisademeglio/electron4-setA11yTreeEnabled.git
  $ yarn install
  $ yarn start

atom/browser/api/atom_api_app.cc
if (Browser::Get()->is_ready()) {
    args->ThrowError(
        "app.enableSandbox() can only be called "
        "before app is ready");
    return;
  }
  auto* command_line = base::CommandLine::ForCurrentProcess();
  RemoveNoSandboxSwitch(command_line);
  command_line->AppendSwitch(switches::kEnableSandbox);
}
void App::EnableMixedSandbox(mate::Arguments* args) {
  if (Browser::Get()->is_ready()) {
    args->ThrowError(
        "app.enableMixedSandbox() can only be called "
        "before app is ready");
    return;
  }
  auto* command_line = base::CommandLine::ForCurrentProcess();
  RemoveNoSandboxSwitch(command_line);
  command_line->AppendSwitch(switches::kEnableMixedSandbox);
}
#if defined(OS_MACOSX)
bool App::MoveToApplicationsFolder(mate::Arguments* args) {
  return ui::cocoa::AtomBundleMover::Move(args);
}
bool App::IsInApplicationsFolder() {
  return ui::cocoa::AtomBundleMover::IsCurrentAppInApplicationsFolder();
}
#endif
mate::Handle<App> App::Create(v8::Isolate* isolate) {