* **Electron Version** (output of `node_modules/.bin/electron --version`):
  * v4.0.5
* **Operating System** (Platform and Version):
  *  Windows 10 

### Expected Behavior
using  webContents api to print an html file oriention  set to landscape in default printer settings and page size set to A5, 

mainWindow.webContents.print({ silent: true, printBackground: false, deviceName: 'HP LaserJet 1020' })

My issue is : it is not printing as defined in the default printer settings

but it currently printing is deviceName not set

and need to send mainWindow.webContents.print() api to silently and printer name 

### To Reproduce
If you provide a URL, please list the commands required to clone/setup/run your repo e.g.
```sh
$ git clone git@github.com:shabeer-mdy/electron-quick-start.git
$ npm install
$ npm start || electron .
```
and set any printer name to  mainWindow.webContents.print({ silent: true, printBackground: false, deviceName: 'HP LaserJet 1020' })

set any installed printer name 



shell/browser/api/atom_api_web_contents.cc
mate::Dictionary margins;
  if (options.Get("margins", &margins)) {
    printing::MarginType margin_type = printing::DEFAULT_MARGINS;
    margins.Get("marginType", &margin_type);
    settings.SetInteger(printing::kSettingMarginsType, margin_type);
    if (margin_type == printing::CUSTOM_MARGINS) {
      int top = 0;
      margins.Get("top", &top);
      settings.SetInteger(printing::kSettingMarginTop, top);
      int bottom = 0;
      margins.Get("bottom", &bottom);
      settings.SetInteger(printing::kSettingMarginBottom, bottom);
      int left = 0;
      margins.Get("left", &left);
      settings.SetInteger(printing::kSettingMarginLeft, left);
      int right = 0;
      margins.Get("right", &right);
      settings.SetInteger(printing::kSettingMarginRight, right);
    }
  } else {
    settings.SetInteger(printing::kSettingMarginsType,
                        printing::DEFAULT_MARGINS);
  }
  settings.SetBoolean(printing::kSettingHeaderFooterEnabled, false);
  
  bool print_color = true;
  options.Get("color", &print_color);
  int color_setting = print_color ? printing::COLOR : printing::GRAY;
  settings.SetInteger(printing::kSettingColor, color_setting);
  bool landscape = false;