By the compatible logic in DisplayPolicy.layoutWidnowLw(), if a regular
window (non-TYPE_STATUS_BAR_PANEL, non-TYPE_TOAST, and
non-TYPE_SYSTEM_ALERT) doesn't extend into any of system bars, it should
fit IME.
The logic was implemented by pf.set(displayFrames.mContent) in the
legacy insets mode, where mContent would be adjusted after processing
IME.
Fix: 149838078
Test: Steps in the target issue
Test: atest ViewRootImplTest
Change-Id: I6eb685fa1e3ad9789621e5647fc490300054db8b
5fb9ab7ddf