Build the NDK compliant shared library to be used by JNI in SkQP.

This CL creates a new build target with a customized set of GN
flags that enable the native components of SkQP to be built using
NDK APIs.

Bug: skia:12777
Change-Id: I8341eafa7fc794cfb759045b7c7238e69c29b0a3
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/491447
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Derek Sollenberger <djsollen@google.com>
7 files changed