Add a script to fetch the latest SKPs.

I keep forgetting how best to do this.

NOTRY=true
NOTREECHECKS=true

Review URL: https://codereview.chromium.org/880283002
diff --git a/bin/fetch-skps b/bin/fetch-skps
new file mode 100755
index 0000000..5512b6e
--- /dev/null
+++ b/bin/fetch-skps
@@ -0,0 +1,9 @@
+#!/bin/sh
+
+# Copies the latest bot-generated SKP set to ./skps.
+
+set -x
+set -e
+
+VERSION=`cat $(dirname $0)/../SKP_VERSION`
+gsutil -m cp -r gs://chromium-skia-gm/playback_$VERSION/skps .