* 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
bool succeed = false;
  base::FilePath path;
  int key = GetPathConstant(name);
  if (key >= 0)
    succeed = base::PathService::Get(key, &path);
  if (!succeed)
    args->ThrowError("Failed to get '" + name + "' path");
  return path;
}
void App::SetPath(mate::Arguments* args,
                  const std::string& name,
                  const base::FilePath& path) {
  if (!path.IsAbsolute()) {
    args->ThrowError("Path must be absolute");
    return;
  }
  bool succeed = false;
  int key = GetPathConstant(name);
  if (key >= 0)
    succeed =
        base::PathService::OverrideAndCreateIfNeeded(key, path, true, false);
  if (!succeed)
    args->ThrowError("Failed to set path");
}
void App::SetDesktopName(const std::string& desktop_name) {