* **Electron Version** (output of `node_modules/.bin/electron --version`):
  * 3.0.6
* **Operating System** (Platform and Version):
  * macOS 10.14

### Expected Behavior
a `new-window` event fires

### Actual behavior
a `did-fail-load` fires with errorCode -3

### To Reproduce
```sh
$ git clone git@github.com:chrismohr/no-new-window.git -b master
$ cd no-new-window/
$ npm i && npm start
```

atom/browser/web_contents_preferences.cc
if (IsEnabled(options::kOffscreen)) {
    command_line->AppendSwitch(options::kOffscreen);
  }
  
  int guest_instance_id = 0;
  if (GetAsInteger(&preference_, options::kGuestInstanceID, &guest_instance_id))
    command_line->AppendSwitchASCII(switches::kGuestInstanceID,
                                    base::NumberToString(guest_instance_id));
  
  int opener_id;
  if (GetAsInteger(&preference_, options::kOpenerID, &opener_id))
    command_line->AppendSwitchASCII(switches::kOpenerID,
                                    base::NumberToString(opener_id));
#if defined(OS_MACOSX)
  
  if (IsEnabled(options::kScrollBounce))
    command_line->AppendSwitch(switches::kScrollBounce);
#endif
  
  auto* args =
      preference_.FindKeyOfType("commandLineSwitches", base::Value::Type::LIST);
  if (args) {
    for (const auto& arg : args->GetList()) {
      if (arg.is_string()) {
        const auto& arg_val = arg.GetString();
        if (!arg_val.empty())
          command_line->AppendSwitch(arg_val);
      }
    }
  }