* 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/browser.h
CRITICAL = 0,        
    INFORMATIONAL = 10,  
  };
  int DockBounce(BounceType type);
  void DockCancelBounce(int request_id);
  
  void DockDownloadFinished(const std::string& filePath);
  
  void DockSetBadgeText(const std::string& label);
  std::string DockGetBadgeText();
  
  void DockHide();
  v8::Local<v8::Promise> DockShow(v8::Isolate* isolate);
  bool DockIsVisible();
  
  void DockSetMenu(AtomMenuModel* model);
  
  void DockSetIcon(const gfx::Image& image);
#endif  
#if defined(OS_MACOSX) || defined(OS_LINUX)
  void ShowAboutPanel();
  void SetAboutPanelOptions(const base::DictionaryValue& options);
#endif