Configure handwriting window with the IME's pid and uid for ANRs

When starting a handwriting session, update the handwriting input window
so that it is configured with the IME's pid and uid. This means any ANRs
that occur due to the handwriting input window will be directed to the
IME process.

Since oneway binder calls do not have pid information, we cannot use
Binder.getCallingPid() to get the pid of the IME. Instead, we report the
pid from IMS when starting handwriting.

Bug: 210978621
Test: manual with custom IME, verify ANR is directed to IME.
Change-Id: Ia6963eb02cad22c7f604896e6c78ed31c84e32f6