No need to deal with windowTokens

we have a link to the client which is enough to find the views.

Also there was some cases where the windowToken was not updated
properly. This is moot now.

Also: Read a array of views from the client to speed up the
client<->AutofillManager communication.

Fixes: 38070352
Test: CtsAutoFillServiceTestCases
      1 Started autofill, saw fill UI
      2 Home button
      3 Kill activity in background
      4 Recents -> back to activity
      5 Saw fill UI restored
Change-Id: I7c2c9411204fa5d65867efae9b7296399121c3a2