Forward declare ANativeWindow, and remove <hardware/gralloc.h> where
GrallocAndroid.hpp already includes it.

Change-Id: Idebd4c40280960ff00cd51b6633c1c84a8cf7de2
Reviewed-on: https://swiftshader-review.googlesource.com/11288Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>