Unleak blink's internals from web_graphics_context_3d_provider.h

A change included an internal blink header in the public api
layer which then leaked parts of blink's internal out into the
wild dangerous world outside. This is a quick fix to close that
leak. Might need some tuning.

Bug: 902022
Change-Id: I076f4c5d0a27cd4c3070d8fe8a5be97f2f65e1e0
Reviewed-on: https://chromium-review.googlesource.com/c/1323715
Commit-Queue: Daniel Bratell <bratell@opera.com>
Reviewed-by: enne <enne@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606409}
4 files changed