Once you have downloaded an android NDK, you can set the ndk GN arg to use it.
E.g. my gn.args looks like:
is_debug = false
ndk = "/opt/android-ndk"
This should be enough to get you going for an arm64 build. You ought to be able to tweak that to other architectures by changing target_cpu to "arm", "x86", "x86-64", etc. That won't quite work until I follow this up a bit, but the skeleton is there.
This is enough to get me compiled, linked, and running to completion on my N5x.
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2275983004
Review-Url: https://codereview.chromium.org/2275983004