[devserver] Support downloading nativetests artifact

BUG=b:27410319
TEST=local devserver

Change-Id: Iafc9742f08564dfc4bd151d5b24733ee8791dc6d
Reviewed-on: https://chromium-review.googlesource.com/333111
Commit-Ready: Simran Basi <sbasi@chromium.org>
Tested-by: Simran Basi <sbasi@chromium.org>
Reviewed-by: Dan Shi <dshi@google.com>
diff --git a/artifact_info.py b/artifact_info.py
index 6f219cd..3f24cb5 100644
--- a/artifact_info.py
+++ b/artifact_info.py
@@ -94,6 +94,9 @@
 # Zip file of vendor partitions used by Brillo device.
 ANDROID_VENDOR_PARTITION_ZIP = 'vendor_partitions'
 
+# Zip file of native tests used by Android devices.
+ANDROID_NATIVETESTS_ZIP = 'nativetests'
+
 # In general, downloading one artifact usually indicates that the caller will
 # want to download other artifacts later. The following map explicitly defines
 # this relationship. Specifically: