Remove GrGLGpu member vars related to already removed clear-as-draw program.

Change-Id: Id193e4ccee77323dd172b83e7d90f94a2691466f
Reviewed-on: https://skia-review.googlesource.com/c/187301
Commit-Queue: Brian Salomon <bsalomon@google.com>
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
Auto-Submit: Brian Salomon <bsalomon@google.com>
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
2 files changed