* Electron version: 1.6.10
* Operating system: macOS Sierra 10.12.4 (16E195)

# Improve Handoff API support

Hi!

Today the API of Handoff provides the methods: `setUserActivity`, `getCurrentActivityType` and dispatch the event `continue-activity`

I'm using Handoff and noticed that in some circumstances the broadcast takes a long time to update its userInfo which does not happen on the native iOS client

1. To invalidate or resign the current activity we currently need to create a non-existing activity type and set it as the current activity. There's no way to handle the activity life cycle through electron.
2. When we need to update a given user activity userInfo frequently (i.e in response to a search bar's text changes), we have no efficient way. Setting a new userActivity with the updated information takes several seconds to bridge, whereas doing this on iOS native app is instantaneous.

I believe that exposing a bit more of the NSUserActivity API to Electron would help, namely `becomeCurrent`, `resignCurrent` and `invalidate` which would address point 1, and `needsSave` and a new event to allow updating an activity when needed to address point 2.
These are described in more detail in https://developer.apple.com/reference/foundation/nsuseractivity.

I'm are open to help in any way i can such as explaining how the native API work, providing sample code or testing possible implementations

Thank you!
atom/browser/api/atom_api_app.cc
dock_.Reset(isolate, dock_obj.GetHandle());
  }
  return v8::Local<v8::Value>::New(isolate, dock_);
}
#endif
mate::Handle<App> App::Create(v8::Isolate* isolate) {
  return mate::CreateHandle(isolate, new App(isolate));
}
void App::BuildPrototype(v8::Isolate* isolate,
                         v8::Local<v8::FunctionTemplate> prototype) {
  prototype->SetClassName(mate::StringToV8(isolate, "App"));
  auto browser = base::Unretained(Browser::Get());
  mate::ObjectTemplateBuilder(isolate, prototype->PrototypeTemplate())
      .SetMethod("quit", base::BindRepeating(&Browser::Quit, browser))
      .SetMethod("exit", base::BindRepeating(&Browser::Exit, browser))
      .SetMethod("focus", base::BindRepeating(&Browser::Focus, browser))
      .SetMethod("getVersion",
                 base::BindRepeating(&Browser::GetVersion, browser))
      .SetMethod("setVersion",
                 base::BindRepeating(&Browser::SetVersion, browser))
      .SetMethod("_getName", base::BindRepeating(&Browser::GetName, browser))
      .SetMethod("_setName", base::BindRepeating(&Browser::SetName, browser))
      .SetMethod("isReady", base::BindRepeating(&Browser::is_ready, browser))
      .SetMethod("whenReady", base::BindRepeating(&Browser::WhenReady, browser))
      .SetMethod("addRecentDocument",
                 base::BindRepeating(&Browser::AddRecentDocument, browser))
      .SetMethod("clearRecentDocuments",
                 base::BindRepeating(&Browser::ClearRecentDocuments, browser))
      .SetMethod("setAppUserModelId",
                 base::BindRepeating(&Browser::SetAppUserModelID, browser))