Once the more advanced GlTextureProcessor interface exists,
it will be possible to change the output size of a GlTextureProcessor
between frames. To keep the re-configuration based on the frame sizes
minimal, things indepedent of the frame size, such as the GlProgram,
can be initialized in the constructor.
PiperOrigin-RevId: 451997584
(cherry picked from commit 54d44d38)
