- 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
const std::string& file_system_id,
                                  const std::string& file_system_path,
                                  const std::string& type) {
  const GURL origin = ontents->GetURL().GetOrigin();
  std::string file_system_name =
      storage::GetIsolatedFileSystemName(origin, file_system_id);
  std::string root_url = storage::GetIsolatedFileSystemRootURIString(
      origin, file_system_id, kRootName);
  return FileSystem(type, file_system_name, root_url, file_system_path);
}
std::unique_ptr<base::DictionaryValue> CreateFileSystemValue(
    const FileSystem& file_system) {
  std::unique_ptr<base::DictionaryValue> file_system_value(
      new base::DictionaryValue());
  file_system_value->SetString("type", file_system.type);
  file_system_value->SetString("fileSystemName", file_system.file_system_name);
  file_system_value->SetString("rootURL", file_system.root_url);
  file_system_value->SetString("fileSystemPath", file_system.file_system_path);
  return file_system_value;
}
void WriteToFile(const base::FilePath& path, const std::string& content) {
  base::ScopedBlockingCall scoped_blocking_call(FROM_HERE,
                                                base::BlockingType::WILL_BLOCK);
  DCHECK(!path.empty());
  base::WriteFile(path, content.data(), content.size());
}
void AppendToFile(const base::FilePath& path, const std::string& content) {