Add envvar GOOGLE_CHRONICLE_INSTANCE_ID for tests (#12536)

[upstream:0052688447f35fe46cecb1f418520295f9007b9c]

Signed-off-by: Modular Magician <[email protected]>

.changelog/12536.txt

@@ -0,0 +1,3 @@
+```release-note:none
+
+```

google-beta/envvar/envvar_utils.go

@@ -106,6 +106,13 @@ var PapDescriptionEnvVars = []string{
 	"GOOGLE_PUBLIC_AVERTISED_PREFIX_DESCRIPTION",
 }
 
+// This value is the instance id of a pre-configured Chronicle instance, for the purpose of
+// integration tests. It is needed because the instance is 1-to-1 with a test project, and it
+// cannot be created within the test org.
+var ChronicleInstanceIdEnvVars = []string{
+	"GOOGLE_CHRONICLE_INSTANCE_ID",
+}
+
 var ImpersonateServiceAccountEnvVars = []string{
 	"GOOGLE_IMPERSONATE_SERVICE_ACCOUNT",
 }
@@ -205,6 +212,11 @@ func GetTestPublicAdvertisedPrefixDescriptionFromEnv(t *testing.T) string {
 	return transport_tpg.MultiEnvSearch(PapDescriptionEnvVars)
 }
 
+func GetTestChronicleInstanceIdFromEnv(t *testing.T) string {
+	SkipIfEnvNotSet(t, ChronicleInstanceIdEnvVars...)
+	return transport_tpg.MultiEnvSearch(ChronicleInstanceIdEnvVars)
+}
+
 func SkipIfEnvNotSet(t *testing.T, envs ...string) {
 	if t == nil {
 		log.Printf("[DEBUG] Not running inside of test - skip skipping")