- 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
base::ProcessId plugin_pid) {
#if BUILDFLAG(ENABLE_PLUGINS)
  content::WebPluginInfo info;
  auto* plugin_service = content::PluginService::GetInstance();
  plugin_service->GetPluginInfoByPath(plugin_path, &info);
  Emit("plugin-crashed", info.name, info.version);
#endif  
}
void WebContents::MediaStartedPlaying(const MediaPlayerInfo& video_type,
                                      const content::MediaPlayerId& id) {
  Emit("media-started-playing");
}
void WebContents::MediaStoppedPlaying(
    const MediaPlayerInfo& video_type,
    const content::MediaPlayerId& id,
    content::WebContentsObserver::MediaStoppedReason reason) {
  Emit("media-paused");
}
void WebContents::DidChangeThemeColor() {
  auto theme_color = ontents()->GetThemeColor();
  if (theme_color) {
    Emit("did-change-theme-color", electron::ToRGBHex(theme_color.value()));
  } else {
    Emit("did-change-theme-color", nullptr);
  }
}
void WebContents::OnInterfaceRequestFromFrame(