Dawn: build libdawn-native as a static lib, not shared.

Also clean up the main BUILD.gn file to use deps instead of public_deps
where possible.

Change-Id: I2cc7719e42ae70be9181bdb02a1995cd2c780672
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/249177
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Stephen White <senorblanco@chromium.org>
2 files changed