Use swarming in capture_archives CT task and capture archives in parallel

ct/go/util/constants.go

Index: ct/go/util/constants.go
diff --git a/ct/go/util/constants.go b/ct/go/util/constants.go
index efd4167be3cbfa9022945773c81d8fca8a84d003..4ce6ad8eafba3d3ddd78786af59dbe07128d91f8 100644
--- a/ct/go/util/constants.go
+++ b/ct/go/util/constants.go
@@ -186,11 +186,14 @@ const (
 	WEBHOOK_SALT_MSG = `For prod, set this file to the value of GCE metadata key webhook_request_salt or call webhook.MustInitRequestSaltFromMetadata() if running in GCE. For testing, run 'echo -n "notverysecret" | base64 -w 0 > /b/storage/webhook_salt.data' or call frontend.InitForTesting().`
 
 	// Swarming constants.
-	SWARMING_DIR_NAME    = "swarming"
-	SWARMING_POOL        = "CT"
+	SWARMING_DIR_NAME = "swarming"
+	SWARMING_POOL     = "CT"
+	// Timeouts.
 	BATCHARCHIVE_TIMEOUT = 10 * time.Minute
+	XVFB_TIMEOUT         = 5 * time.Minute
 	// Isolate files.
-	CREATE_PAGESETS_ISOLATE = "create_pagesets.isolate"
+	CREATE_PAGESETS_ISOLATE  = "create_pagesets.isolate"
+	CAPTURE_ARCHIVES_ISOLATE = "capture_archives.isolate"
 )
 
 type PagesetTypeInfo struct {
@@ -217,6 +220,7 @@ var (
 	// Names of local directories and files.
 	StorageDir           = filepath.Join("/", "b", STORAGE_DIR_NAME)
 	RepoDir              = filepath.Join("/", "b", REPO_DIR_NAME)
+	DepotToolsDir        = filepath.Join("/", "b", "depot_tools")
 	GomaDir              = filepath.Join("/", "b", "build", "goma")
 	ChromiumBuildsDir    = filepath.Join(StorageDir, CHROMIUM_BUILDS_DIR_NAME)
 	ChromiumSrcDir       = filepath.Join(StorageDir, "chromium", "src")