Roll forward of "Revert "TouchMode (5/n) Implementing onTouchModeChanged""

This reverts commit 8e8e721f.

Reason for revert: ViewRootImpl#windowFocusChanged to also change touch
mode.

Fixes: 173468133
Bug: 193718270
Test: atest FrameworksCoreTests CtsWindowManagerDeviceTestCases

Change-Id: I21780b86574c395cd6c2c5c05a88078c050edb8c