Make GrGLSLPrimitiveProcessor::emitTransforms take local coords as GrShaderVar.

Also remove unused position variable parameter.

Change-Id: I37f98a03ac1ca750810de13b08e3ffa11e41828c
Reviewed-on: https://skia-review.googlesource.com/81320
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
16 files changed