Add synchronous transaction to wait for setInputWindow to complete (5/n)

Added syncInputWindows method to JNI and SurfaceControl.Transaction

This enables the caller to request SF to wait until input windows have
been synced with InputDispatcher.

Bug: 123041491
Test: builds, runs
Change-Id: I2ddaa3f43eded2fb117cc2850ee7c8a20b2b63ec
2 files changed