Ensure we flush TextBlobCache message queue.

If we create and delete TextBlobs without actually renderering them,
their deletion messages can back up in the message queue. This adds
a routine to GrContext to ensure these messages get flushed.

Bug: 703297
Change-Id: Icc222373ac2a954dc3b77190cad79070ea562ba2
Reviewed-on: https://skia-review.googlesource.com/82686
Commit-Queue: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
4 files changed