the core screenshot function now can capture the screen at any lower resolution
performing bilinear filtering.
we also now have some client code to interface with the screenshot service.
it's now possible to request a screenshot at a lower resolution.
Change-Id: I33689bba98507ab928d0898b21596d0d2fe4b953
SurfaceComposerClient now only exist on the WindowManager side,
the client side uses the new SurfaceClient class, which only
exposes what a client needs.
also instead of keeping mappings from IBinder to SurfaceComposerClients
we have a SurfaceClient per Surface (referring to the same IBinder), this
is made possible by the fact that SurfaceClient is very light.
Change-Id: I6a1f7015424f07871632a25ed6a502c55abfcfa6
