Revert "Treat UNKNOWN tooltype events as Mouse events."

https://buganizer.corp.google.com/u/0/issues/24904588 has been fixed.

This reverts commit 260c6980cef923792c352dc8143be5cb93a3af55.

Change-Id: I341513c06a7bfda364b0efd675e785ce766d5819
1 file changed