Rename GrBatchAtlas files to GrDrawOpAtlas

This intermediary change only exists to make the actual class rename change readable on gerrit due to gerrit not recognizing file renames correctly.

Change-Id: I919f84837fb17191ca49f00f82e56330f84766da
Reviewed-on: https://skia-review.googlesource.com/6190
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
10 files changed