- 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,
                     electron::api::WebContents::Type* out) {
    using Type = electron::api::WebContents::Type;
    std::string type;
    if (!ConvertFromV8(isolate, val, &type))
      return false;
    if (type == "backgroundPage") {
      *out = Type::kBackgroundPage;
    } else if (type == "browserView") {
      *out = Type::kBrowserView;
    } else if (type == "webview") {
      *out = Type::kWebView;
#if BUILDFLAG(ENABLE_OSR)
    } else if (type == "offscreen") {
      *out = Type::kOffScreen;
#endif
    } else {
      return false;
    }
    return true;
  }
};
template <>
struct Converter<scoped_refptr<content::DevToolsAgentHost>> {
  static v8::Local<v8::Value> ToV8(