Merge pull request #13541 from RudyLu/keyboard/Bug935979-Intermittent_jspinyin_error

 Bug 935979 - [keyboard] Intermittent Travis unit test failure: jspinyin...
r=me, a=test-only
Bug 936157 - [Messages] Bug 928821 breaks the desktop mock r=schung
Bug 913783 - Enable language-associated keyboard layouts.
 - add unit tests for layout changes