When using a MatrixTransformationFrameProcessor per transformation
matrix, each frame processor's shader applies the matrix to the
vertices and clips the result to the NDC range when drawing the
output frame.
This change combines consecutive MatrixTransformations into a single
MatrixTransformationFrameProcessor by multiplying the individual
matrices while updating and clipping the visible polygon after
each matrix and mapping the resulting visible polygon back to the
input space so that its vertices and the combined transformation
matrix can be used in the shader.
PiperOrigin-RevId: 448521068
d59186e53c