Block touches from passing through activities

By setting an InputWindowHandle for ActivityRecord it is no longer
possible for Activities to shrink their own window size to allow touches
to pass through to activities behind. The touchable region is cropped by
the parent, meaning that it will occupy all availble space.

Feature is disabled by default and can be enabled per package using adb
shell am compat enable ENABLE_TOUCH_OPAQUE_ACTIVITIES <package>

Test: Manually enabled appcompat feature and verified with sample from
b/194480991 that touches are blocked.
Bug: 194480991
Bug: 196054901

Change-Id: I5cc782953bf9bf855f7e49041a0f784a7aae6934