NVIDIA drivers sometimes go into infinite loops in this code, jbauman@
speculated that these drivers may need to do the flush in the GetData call.

BUG=626849

Change-Id: I85408fbe7176242240862225e968f557bd7818cf
Reviewed-on: https://chromium-review.googlesource.com/360130Reviewed-by: John Bauman <jbauman@chromium.org>
Commit-Queue: Geoff Lang <geofflang@chromium.org>