Reparent IME container to the root of the IME target window

Reparent IME container so that it's bounds and config will be updated to
match the RootDisplayArea.

Bug: 156355859
Test: manual: test with dual display policy
Change-Id: Ia9c4f6c73c2a6b8ecbf2cd9f6feb39967ebff80c
8 files changed