- 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 base::FilePath& path) {
  auto* isolated_context = storage::IsolatedContext::GetInstance();
  std::string root_name(kRootName);
  storage::IsolatedContext::ScopedFSHandle file_system =
      isolated_context->RegisterFileSystemForPath(
          storage::kFileSystemTypeLocal, std::string(), path, &root_name);
  content::ChildProcessSecurityPolicy* policy =
      content::ChildProcessSecurityPolicy::GetInstance();
  content::RenderViewHost* render_view_host = ontents->GetRenderViewHost();
  int renderer_id = render_view_host->GetProcess()->GetID();
  policy->GrantReadFileSystem(renderer_id, file_system.id());
  policy->GrantWriteFileSystem(renderer_id, file_system.id());
  policy->GrantCreateFileForFileSystem(renderer_id, file_system.id());
  policy->GrantDeleteFromFileSystem(renderer_id, file_system.id());
  if (!policy->CanReadFile(renderer_id, path))
    policy->GrantReadFile(renderer_id, path);
  return file_system.id();
}
FileSystem CreateFileSystemStruct(content::WebContents* ontents,