devserver: Add support for control_files.tar and autotest_packages.tar

We are splitting up the autotest.tar tarball into 2 separate tarballs.
This change updates the devserver code so that it is able to properly
stage these artifacts.

BUG=chromium:421122
TEST=local devserver and local moblab build that tested a trybot image
with no autotest.tar artifact.

Change-Id: I546add63b74906ce2969e45f8209e074bed02b5c
Reviewed-on: https://chromium-review.googlesource.com/226822
Reviewed-by: Prashanth B <beeps@chromium.org>
Reviewed-by: Yu-Ju Hong <yjhong@chromium.org>
Commit-Queue: Simran Basi <sbasi@chromium.org>
Tested-by: Simran Basi <sbasi@chromium.org>
diff --git a/artifact_info.py b/artifact_info.py
index 89fbf3e..0a5c674 100644
--- a/artifact_info.py
+++ b/artifact_info.py
@@ -40,6 +40,12 @@
 # Autotest -- the main autotest directory without the test_suites subdir.
 AUTOTEST = 'autotest'
 
+# Control Files -- the autotest control files without the test_suites subdir.
+CONTROL_FILES = 'control_files'
+
+# Autotest Packages-- the autotest packages subdirectory.
+AUTOTEST_PACKAGES = 'autotest_packages'
+
 # Test Suites - just the test suites control files from the autotest directory.
 TEST_SUITES = 'test_suites'
 
diff --git a/build_artifact.py b/build_artifact.py
index 68fc72b..ae55848 100755
--- a/build_artifact.py
+++ b/build_artifact.py
@@ -28,6 +28,8 @@
 AU_SUITE_FILE = 'au_control.tar.bz2'
 PAYGEN_AU_SUITE_FILE_TEMPLATE = 'paygen_au_%(channel)s_control.tar.bz2'
 AUTOTEST_FILE = 'autotest.tar'
+CONTROL_FILES_FILE = 'control_files.tar'
+AUTOTEST_PACKAGES_FILE = 'autotest_packages.tar'
 AUTOTEST_COMPRESSED_FILE = 'autotest.tar.bz2'
 DEBUG_SYMBOLS_FILE = 'debug.tgz'
 FACTORY_FILE = 'ChromeOS-factory*.zip'
@@ -573,6 +575,10 @@
     ImplDescription(AutotestTarballBuildArtifact, AUTOTEST_FILE,
                     files_to_extract=None,
                     exclude=['autotest/test_suites']),
+    artifact_info.CONTROL_FILES:
+    ImplDescription(BundledBuildArtifact, CONTROL_FILES_FILE),
+    artifact_info.AUTOTEST_PACKAGES:
+    ImplDescription(AutotestTarballBuildArtifact, AUTOTEST_PACKAGES_FILE),
     artifact_info.TEST_SUITES:
     ImplDescription(BundledBuildArtifact, TEST_SUITES_FILE),
     artifact_info.AU_SUITE: