Start using some better sorting for intent resolution

Previously we used time in foreground as our sole signal. Now, also
use time since last launch and launch count as signals.

Still to come later: launch count based on specific component name
rather than package, pending the recording of that information in
usage stats.

Change-Id: Ic449cae396cfee797b7bb3de9dc3c0da5da2f96c
2 files changed