Fix crash when drawing a GPU-backed surface onto raster.

We now null-check the result of recordingContext() before using it.

Thanks cqjjjzr2@gmail.com for the initial discovery and suggested fix.

Change-Id: Iafcf306f8cd9deb7147ef9c5c71a21907eedc01f
Bug: skia:12214
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/429098
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
3 files changed