Use vkGetPhysicalDeviceSurfaceCapabilitiesKHR() instead of
ANativeWindow_getWidth() & ANativeWindow_getHeight().  The former
gives the proper size of the window, where the latter gives the size
of the device's display (which is the default size of a window).

Bug: b/168327817
Change-Id: I524116b7b07bf2ec7637fe2874806c5eb8318171
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2464920Reviewed-by: Tim Van Patten <timvp@google.com>
Reviewed-by: Courtney Goeltzenleuchter <courtneygo@google.com>
Commit-Queue: Ian Elliott <ianelliott@google.com>