the deadlock would happen when the pipe became invalid and SF
trying to remove the connection from its list.
we know make sure to process events without holding a lock.
Change-Id: I39927ed8824fc7811e16db3c7608a2ebc72d9642
use gui/DisplayEvent to receive the events. Events are
dispatched through a unix pipe, so the API is compatible
with utils/Looper. see gui/DisplayEvent.h for more info.
Bug: 1475048
Change-Id: Ia720f64d1b950328b47b22c6a86042e481d35f09