EGLWindow does nothing with it per se, but some code was relying on it
to store it. Add width and height to ANGLETest and SampleApplication
instead. Also fix a typo in PerfTestParams, widowWidth -> windowWidth.

BUG=angleproject:1105

Change-Id: I26da607a2e6342864b508a50ee3cf8944608f868
Reviewed-on: https://chromium-review.googlesource.com/287379Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Corentin Wallez <cwallez@chromium.org>