Implement directed recovery snapshot.

Bug: 177451657
Test: m -j nothing
Change-Id: I0b84c34fb2e9e9340d9f9e7405428cd2cc4d43b5
diff --git a/android/config.go b/android/config.go
index e0f3a91..50e39d7 100644
--- a/android/config.go
+++ b/android/config.go
@@ -1413,6 +1413,14 @@
 	return c.config.productVariables.VendorSnapshotModules
 }
 
+func (c *deviceConfig) DirectedRecoverySnapshot() bool {
+	return c.config.productVariables.DirectedRecoverySnapshot
+}
+
+func (c *deviceConfig) RecoverySnapshotModules() map[string]bool {
+	return c.config.productVariables.RecoverySnapshotModules
+}
+
 // The ConfiguredJarList struct provides methods for handling a list of (apex, jar) pairs.
 // Such lists are used in the build system for things like bootclasspath jars or system server jars.
 // The apex part is either an apex name, or a special names "platform" or "system_ext". Jar is a