isDefaultActiveApp is called on every package. We can cache default
dialer and default sms package in a list, and check if the list
contains target package name.
Fixes: 140279638
Bug: 151233929
Test: manual, make RunSettingsLibRoboTests
Change-Id: I81f5ccb7aed1ebec797a21af6094971e05f456a7
(cherry picked from commit 19c2bbccfd)
Unit test suite for SettingsLib using Robolectric.
$ croot
$ make RunSettingsLibRoboTests -j40