This code shares the Window and EGL logic between the two
projects.

BUG=angle:730

Change-Id: I8940371226a8f7b02579c332f51679c4a5d0e2a5
Reviewed-on: https://chromium-review.googlesource.com/212799Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Brandon Jones <bajones@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>