The destructors of objects in a context assume that the context is current
during destruction. If another context is current at this time, they can
delete objects from other contexts.
BUG=angleproject:2464
Change-Id: I813d092cc7f33a39c814edae5baa433733b4590c
Reviewed-on: https://chromium-review.googlesource.com/1083371
Commit-Queue: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
