Add a variable to specify standalone system server jars.

This is the list of jars that system_server loads dynamically using
separate classloaders. We will rely on this variable to decide which
jars to preopt in the build system and on the device for system_server.

The list is supposed to be in sync with the code in SystemServer.java.
There will be a follow-up CL to add a comment in SystemServer.java to
remind developers to keep them in sync.

Bug: 203198541
Test: m nothing
Change-Id: I305a73218ef2d2c61ac3795d21026b2afe7007fd
diff --git a/core/product.mk b/core/product.mk
index 503b44f..31b1beb 100644
--- a/core/product.mk
+++ b/core/product.mk
@@ -232,9 +232,15 @@
 _product_single_value_vars += PRODUCT_SUPPORTS_VERITY
 _product_single_value_vars += PRODUCT_SUPPORTS_VERITY_FEC
 _product_list_vars += PRODUCT_SYSTEM_SERVER_APPS
+# List of system_server classpath jars on the platform.
 _product_list_vars += PRODUCT_SYSTEM_SERVER_JARS
-# List of system_server jars delivered via apex. Format = <apex name>:<jar name>.
+# List of system_server classpath jars delivered via apex. Format = <apex name>:<jar name>.
 _product_list_vars += PRODUCT_APEX_SYSTEM_SERVER_JARS
+# List of jars on the platform that system_server loads dynamically using separate classloaders.
+_product_list_vars += PRODUCT_STANDALONE_SYSTEM_SERVER_JARS
+# List of jars delivered via apex that system_server loads dynamically using separate classloaders.
+# Format = <apex name>:<jar name>
+_product_list_vars += PRODUCT_APEX_STANDALONE_SYSTEM_SERVER_JARS
 # If true, then suboptimal order of system server jars does not cause an error.
 _product_single_value_vars += PRODUCT_BROKEN_SUBOPTIMAL_ORDER_OF_SYSTEM_SERVER_JARS
 # If true, then system server jars defined in Android.mk are supported.