Use EGLClientBuffer in place of HANDLE in EGL.

BUG=angle:795

Change-Id: I7af47e9306e0e12b980cfd3f061bbbe0951ac4e4
Reviewed-on: https://chromium-review.googlesource.com/228913
Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Move as many files as possible from common to libANGLE.

BUG=angle:733

Change-Id: If01c91cd52ac5c2102276a9fdc4b68ebc13e47f9
Reviewed-on: https://chromium-review.googlesource.com/231850
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Geoff Lang <geofflang@chromium.org>
Use cross-platform enum for Vendor ID.

BUG=angle:795

Change-Id: Ibe9bbb79b92730ba80ca7275528c8b61d5d44c59
Reviewed-on: https://chromium-review.googlesource.com/228914
Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>