Revert "Revert "Listen for hover events over stashed taskbar.""

This reverts commit c27605099c14aac3c6f4a7336cf7f573aa0fa780.

Reason for revert: DroidMonitor-triggered revert due to breakage <https://android-build.googleplex.com/builds/quarterdeck?branch=git_udc-dev&target=cf_x86_64_phone-userdebug&lkgb=10076607&lkbb=10076982&fkbb=10076788>, bug <281093059>

Change-Id: I71e7fd07232c27a004243df0ffb0457fe53fe13b
12 files changed