* 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
.SetMethod(
          "isDefaultProtocolClient",
          base::BindRepeating(&Browser::IsDefaultProtocolClient, browser))
      .SetMethod(
          "setAsDefaultProtocolClient",
          base::BindRepeating(&Browser::SetAsDefaultProtocolClient, browser))
      .SetMethod(
          "removeAsDefaultProtocolClient",
          base::BindRepeating(&Browser::RemoveAsDefaultProtocolClient, browser))
      .SetMethod("_setBadgeCount",
                 base::BindRepeating(&Browser::SetBadgeCount, browser))
      .SetMethod("_getBadgeCount",
                 base::BindRepeating(&Browser::GetBadgeCount, browser))
      .SetMethod("getLoginItemSettings", &App::GetLoginItemSettings)
      .SetMethod("setLoginItemSettings",
                 base::BindRepeating(&Browser::SetLoginItemSettings, browser))
      .SetMethod("isEmojiPanelSupported",
                 base::BindRepeating(&Browser::IsEmojiPanelSupported, browser))
      .SetProperty("badgeCount",
                   base::BindRepeating(&Browser::GetBadgeCount, browser),
                   base::BindRepeating(&Browser::SetBadgeCount, browser))
      .SetProperty("name", base::BindRepeating(&Browser::GetName, browser),
                   base::BindRepeating(&Browser::SetName, browser))
#if defined(OS_MACOSX)
      .SetMethod("hide", base::BindRepeating(&Browser::Hide, browser))
      .SetMethod("show", base::BindRepeating(&Browser::Show, browser))
      .SetMethod("setUserActivity",
                 base::BindRepeating(&Browser::SetUserActivity, browser))
      .SetMethod("getCurrentActivityType",
                 base::BindRepeating(&Browser::GetCurrentActivityType, browser))