- 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::string16 final_title;
  bool explicit_set = true;
  if (entry) {
    auto title = entry->GetTitle();
    auto url = entry->GetURL();
    if (url.SchemeIsFile() && title.empty()) {
      final_title = base::UTF8ToUTF16(url.ExtractFileName());
      explicit_set = false;
    } else {
      final_title = title;
    }
  }
  for (ExtendedWebContentsObserver& observer : observers_)
    observer.OnPageTitleUpdated(final_title, explicit_set);
  Emit("page-title-updated", final_title, explicit_set);
}
void WebContents::DidUpdateFaviconURL(
    content::RenderFrameHost* render_frame_host,
    const std::vector<blink::mojom::FaviconURLPtr>& urls) {
  std::set<GURL> unique_urls;
  for (const auto& iter : urls) {
    if (iter->icon_type != blink::mojom::FaviconIconType::kFavicon)
      continue;
    const GURL& url = iter->icon_url;
    if (url.is_valid())
      unique_urls.insert(url);
  }
  Emit("page-favicon-updated", unique_urls);
}
void WebContents::DevToolsReloadPage() {