Bug 1022475 - (Part I) Implement InputAppsTransitionManager
Bug 1022475 - (Part II) Let KeyboardManager use it
Bug 1022475 - (Part III) Fix JS marionette tests
Bug 1022475 - (Part VI) Fix Python tests
Merge pull request #20333 from timdream/input-manage-transition3

Bug 1022475 - Organizing keyboard transition management to another script, r=rudyl