- 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
int32_t ontents_id,
                            const std::string& channel,
                            blink::CloneableMessage arguments) {
  TRACE_EVENT1("electron", "WebContents::MessageTo", "channel", channel);
  auto* target_ontents = FromID(ontents_id);
  if (target_ontents) {
    content::RenderFrameHost* frame = target_ontents->MainFrame();
    DCHECK(frame);
    v8::HandleScope handle_scope(JavascriptEnvironment::GetIsolate());
    gin::HFrameMain> web_frame_main =
        WebFrameMain::From(JavascriptEnvironment::GetIsolate(), frame);
    int32_t sender_id = ID();
    web_frame_main->GetRendererApi()->Message(internal, channel,
                                              std::move(arguments), sender_id);
  }
}
void WebContents::MessageHost(const std::string& channel,
                              blink::CloneableMessage arguments,
                              content::RenderFrameHost* render_frame_host) {
  TRACE_EVENT1("electron", "WebContents::MessageHost", "channel", channel);
   webContents.emit('ipc-message-host', new Event(), channel, args);
  EmitWithSender("ipc-message-host", render_frame_host,
                 electron::mojom::ElectronBrowser::InvokeCallback(), channel,
                 std::move(arguments));
}
void WebContents::UpdateDraggableRegions(