- 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
: ontents(contents) {}
  base::WeakPtr<WebContents> ontents;
};
const void* kElectronApiWebContentsKey = &kElectronApiWebContentsKey;
const char kRootName[] = "<root>";
struct FileSystem {
  FileSystem() = default;
  FileSystem(const std::string& type,
             const std::string& file_system_name,
             const std::string& root_url,
             const std::string& file_system_path)
      : type(type),
        file_system_name(file_system_name),
        root_url(root_url),
        file_system_path(file_system_path) {}
  std::string type;
  std::string file_system_name;
  std::string root_url;
  std::string file_system_path;
};
std::string RegisterFileSystem(content::WebContents* ontents,