Track event flow to IMMS#setImeWindowStatus

This is part of work to introduce historical debugging infrastructure
for Android IME.

In this CL, we will focus on the following two event flows.

 A1. IMMS#attachNewInputLocked() queues MSG_(RE)START_INPUT to deliver
     new InputConnection/EditorInfo to the current IME
 A2. The IME triggers IMS#onStartInput()/IMS#onRestartInput() and
     updates the following fields:
      - InputMethodService#mStartedInputConnection
      - InputMethodService#mInputEditorInfo

 B1. IME is expected to call back IMM#setImeWindowStatus() to notify
     its window visibility change to IMMS.
 B2. IMMS updates the following field if the caller is still the
     current IME.
      - InputMethodManagerService#mImeWindowVis

What this CL aims to do is to enable IMMS to access A1 state when it
was in B2 state, by considering that for given a B1 the last A2
happened before B1 is the cause of B1 and B2.

To do this, IMMS issues a binder token in A1 and each IME keeps it
so that it can be passed in B1. By using this Binder token as a key,
IMMS can keep tracking state snapshot taken from each A1. Note that
those state snapshots keep alive until the Binder token's proxy in the
IME process loses strong reference from its GC root.

Test: Make sure `adb shell dumpsys input_method | grep mImeWindowVis`
      matches to the IME window visibility.
Test: Make sure the current IME is not receiving any
      InvalidParameterException from IMMS.
Bug: 35079353
Change-Id: I9921b381e02106dbffff5e0b3d13f0a1245ce807