Merge pull request #8045 from arcturus/bug-838622

Bug 836170 - [Contact]: Scrolling and Dragging in contact application is very slow(cherry picked from commit 3859bf498196d2c7c640e38b2f9a76061d6a245b)

Conflicts:
	apps/communications/contacts/js/contacts_list.js
	apps/communications/contacts/test/unit/contacts_list_test.js
(cherry picked from commit c48e9ebb04cf089f7db258509b8da76053fdfca4)