- 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
#if !defined(OS_WIN)
  static constexpr base::TaskTraits kTraits = {
      base::MayBlock(), base::TaskPriority::USER_VISIBLE};
#endif
#if defined(USE_CUPS)
  
  return base::ThreadPool::CreateTaskRunner(kTraits);
#elif defined(OS_WIN)
  
  
  return content::GetUIThreadTaskRunner(
      {base::MayBlock(), base::TaskPriority::USER_VISIBLE});
#else
  
  return base::ThreadPool::CreateSingleThreadTaskRunner(kTraits);
#endif
}
#endif
struct UserDataLink : public base::SupportsUserData::Data {
  explicit UserDataLink(base::WeakPtr<WebContents> contents)