Revert "Revert "Bug 938171 - Browser Bookmark Migration to Homescreen in Gaia""

This reverts commit d35f1c9a22c87e96f0289135955f7316900de6ab.
Revert "Revert "Bug 938171 - Add app_migrator module include to bootstrap unit test""

This reverts commit 0acb88a5663af1fa4ec8beb84b7cb657acba19b2.
Bug 938171 - Add MockVersionHelper to bootstrap test for app_migrator module
Bug 1054979 - Do not show overflow menu for apps
Merge pull request #23294 from qdot/revert-revert-938171

Revert revert 938171
Merge pull request #23285 from benfrancis/1054979

Bug 1054979 - Do not show overflow menu for apps r=alive
Revert "Bug 1047143 - close aps entering task-manager, exitToApp to open/restore"

This reverts commit 1d9a8cf867f281d7ab22402f246bac48d0980c33.
Bug 1047118 - Instrumentation compatible with aforementioned bug added to verticalhome to gain more visibility into boot performance.