Bug 1018035 - [Flame][v1.4][SMS]No cursor display when tap the message edit box.  r=azasypkin

(cherry picked from commit 534f9cf57b3fd85f7e408709a7f535e1b8ca3e81)

Conflicts:
	apps/sms/js/compose.js
	apps/sms/test/unit/compose_test.js
Merge pull request #20454 from julienw/1018035-v1.4-cursor-hidden-activity

Bug 1018035 - v1.4 cursor hidden activity