- Electron version: 1.2.2
- Operating system: Linux

This is a problem only in linux. It works in OSX.

``` javascript
win.hide()
win.capturePage(function(img){
 // never called
})
```

shell/browser/api/electron_api_web_contents.cc
v8::Local<v8::Value> val,
                     printing::mojom::MarginType* out) {
    std::string type;
    if (ConvertFromV8(isolate, val, &type)) {
      if (type == "default") {
        *out = printing::mojom::MarginType::kDefaultMargins;
        return true;
      }
      if (type == "none") {
        *out = printing::mojom::MarginType::kNoMargins;
        return true;
      }
      if (type == "printableArea") {
        *out = printing::mojom::MarginType::kPrintableAreaMargins;
        return true;
      }
      if (type == "custom") {
        *out = printing::mojom::MarginType::kCustomMargins;
        return true;
      }
    }
    return false;
  }
};
template <>
struct Converter<printing::mojom::DuplexMode> {
  static bool FromV8(v8::Isolate* isolate,