This change partially implements the requested feature. The following
are not supported yet.
- Non-letter key handling on automatic temporary upper case layout.
- Non-letter key handling on shift chording in caps lock layout.
- Hint icons for manual temporary upper case layout are not final ones.
Bug: 3193390
Change-Id: I636da99d1be05b1337935d87c6f4d140661e1cc8
Because there may be very long key, such as space bar on tablet, we
should not use the distance between the touch point and the center of
key as proximity detection. Instead of that, this change uses the
distance between the point and the nearest edge of key as proximity
detection.
Also this change fixes the bug that space key (code 32) was not
counted in proximity detection.
Bug: 3164020
Bug: 3168138
Change-Id: I687f1ce94a8e944c3f6eea0fe00e18ed6e68e278
