This is a reland of 0f083ab0
Original change's description:
> Reinitialize GL_VENDOR string when GPU switches
>
> We already update the GL_RENDERER string. We should do the same for
> GL_VENDOR so this information is passed along correctly.
>
> Bug: chromium:1152212
> Change-Id: I639700bfebdc9e77ec3c6b41fcd6516e8c32139d
> Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2560824
> Reviewed-by: Jonah Ryan-Davis <jonahr@google.com>
> Reviewed-by: Geoff Lang <geofflang@chromium.org>
> Commit-Queue: Jonah Ryan-Davis <jonahr@google.com>
Bug: chromium:1152212
Change-Id: I044313366ce6ce7040e5c203a979b148dcb564dd
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2569364Reviewed-by: Jonah Ryan-Davis <jonahr@google.com>
Commit-Queue: Jonah Ryan-Davis <jonahr@google.com>
