- Electron version: 1.4.3
- Operating system:  @win7
- description:

working on a download app with electron and angular. 
By using webContents.downloadUrl, webContents.session.on('will-download', handler) I can make download function work well, however, I could not find a api to save download progress before closing electron app so that I can restore download when this app is started next time.

Excepted Result:
1. user click 'download' button to download a 1G file.
2. after 500M is downloaded, user quit the app
3. one hour later, user open this app again, and downloading can automatically be restored

atom/browser/api/atom_api_session.cc
.SetMethod("getBlobData", &Session::GetBlobData)
      .SetProperty("cookies", &Session::Cookies)
      .SetProperty("protocol", &Session::Protocol)
      .SetProperty("webRequest", &Session::WebRequest);
}
}  
}  
namespace {
using atom::api::Session;
v8::Local<v8::Value> FromPartition(
    const std::string& partition, mate::Arguments* args) {
  if (!atom::Browser::Get()->is_ready()) {
    args->ThrowError("Session can only be received when app is ready");
    return v8::Null(args->isolate());
  }
  base::DictionaryValue options;
  args->GetNext(&options);
  return Session::FromPartition(args->isolate(), partition, options).ToV8();
}
void Initialize(v8::Local<v8::Object> exports, v8::Local<v8::Value> unused,
                v8::Local<v8::Context> context, void* priv) {
  v8::Isolate* isolate = context->GetIsolate();
  mate::Dictionary dict(isolate, exports);
  dict.Set("Session", Session::GetConstructor(isolate)->GetFunction());
  dict.Set("Cookies", Cookies::GetConstructor(isolate)->GetFunction());
  dict.SetMethod("fromPartition", &FromPartition);
}
}  
NODE_MODULE_CONTEXT_AWARE_BUILTIN(atom_browser_session, Initialize)