BadTokenException is a normal consequence of swapping IMEs while there
is a DO_SHOW_SOFT_INPUT message in the IIMethodWrapper queue. This
race condition cannot be avoided without an unacceptable lock down of
InputMethodManagerService.
Fixes bug 8387663.
Fixes bug 8263462.
Change-Id: I2c21573cf972145ab08e66604cdb9344139a3f31