- 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
background_throttling_ = allowed;
  auto* rfh = ontents()->GetMainFrame();
  if (!rfh)
    return;
  auto* rwhv = rfh->GetView();
  if (!rwhv)
    return;
  auto* rwh_impl =
      static_cast<content::RenderWidgetHostImpl*>(rwhv->GetRenderWidgetHost());
  if (!rwh_impl)
    return;
  rwh_impl->disable_hidden_ = !background_throttling_;
  ontents()->GetRenderViewHost()->SetSchedulerThrottling(allowed);
  if (rwh_impl->is_hidden()) {
    rwh_impl->WasShown({});
  }
}
int WebContents::GetProcessID() const {
  return ontents()->GetMainFrame()->GetProcess()->GetID();
}
base::ProcessId WebContents::GetOSProcessID() const {
  base::ProcessHandle process_handle =
      ontents()->GetMainFrame()->GetProcess()->GetProcess().Handle();
  return base::GetProcId(process_handle);
}
WebContents::Type WebContents::GetType() const {
  return type_;
}
bool WebContents::Equal(const WebContents* ontents) const {