WindowManager RemoteSurfaceTrace infrastructure

Add "wm surface-trace" command which enables tracing of surface
commands to be switched on at runtime. Primarily intended for use
by WM CTS tests. First target in CTS will be to use show/hide
events to eliminate polling in WM tests and increase speed. Next up
looking at things like verifying various transitions and relaunch
scenarios are flicker free. Later we may want to look at a smarter
or more structured format...but it's really not much hassle to parse
the commands off a pipe so I wanted to get us started.

Test: cts-tradefed run singleCommand cts -o --module CtsWindowManagerHostTestCases --test android.server.cts.SurfaceViewMovementTests#testSurfaceMovesWithParent
Change-Id: I1ff912c405a6cb9996ee9b6e2c465d57706191ba
1 file changed