- 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
return ontents()->IsCrashed();
}
void WebContents::ForcefullyCrashRenderer() {
  content::RenderWidgetHostView* view =
      ontents()->GetRenderWidgetHostView();
  if (!view)
    return;
  content::RenderWidgetHost* rwh = view->GetRenderWidgetHost();
  if (!rwh)
    return;
  content::RenderProcessHost* rph = rwh->GetProcess();
  if (rph) {
#if defined(OS_LINUX) || defined(OS_CHROMEOS)
     A generic |CrashDumpHungChildProcess()| is not implemented for Linux.
     Instead we send an explicit IPC to crash on the renderer's IO thread.
    rph->ForceCrash();
#else
     Try to generate a crash report for the hung process.
#ifndef MAS_BUILD
    CrashDumpHungChildProcess(rph->GetProcess().Handle());
#endif
    rph->Shutdown(content::RESULT_CODE_HUNG);
#endif
  }
}
void WebContents::SetUserAgent(const std::string& user_agent) {