The GlFrameProcessor handles everything related to the GLSL program,
the FrameEditor manages the GL context and the data flow including
the input SurfaceTexture and output EGLSurface.
This will be split up further in follow-up CLs so that
GlFrameProcessors can be chained. At this CL, there are no
functional changes intended.
PiperOrigin-RevId: 428779179