Enable reporting touch area/pressure on clapper/glimmer

BUG=chrome-os-partner:27372
TEST=drawing on www.rbyers.net/paint.html and make sure that touch has
     different radius.

Change-Id: If370d903270484e0163aa8244d7b728c579b25a4
Reviewed-on: https://chromium-review.googlesource.com/191951
Reviewed-by: Andrew de los Reyes <adlr@chromium.org>
Commit-Queue: Yufeng Shen <miletus@chromium.org>
Tested-by: Yufeng Shen <miletus@chromium.org>
Reviewed-by: Benson Leung <bleung@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/192502
Reviewed-by: Yufeng Shen <miletus@chromium.org>
4 files changed