SurfaceTexture: improve texture matrix computation

This change reduces the shrinking of the crop rectangle in some cases.  It adds
a way to inform the SurfaceTexture that its texture will be used without
bilinear interpolation, and uses knowledge of the pixel format to avoid
shrinking unecessarily.

Change-Id: I72365f39f74ecb7fcc51b4cf42f2d0fa97727212