Add more enums for the client and process attributes of SystemApi

For the client attribute, we have
- MODULE_APPS for representing APKs implementing modules which are
considered part of the platform
- MODULE_LIBRARIES for representing jars inside modules.

For the process attribute, we have
- SYSTEM_SERVER for representing the system_server process.

For example, @SystemApi(client=MODULE_LIBRARIES,process=ALL) actually
means that the API is meant to be available for classes in the
bootclasspath but not to the classes from the app classloader.

Bug: 140202860
Test: m

Exempt-From-Owner-Approval: cherry-picked from internal

Merged-In: Iba6a564a0967e4d109164849ee6d6500d46469de
(cherry picked from commit 88d5e494c4)
Change-Id: Iba6a564a0967e4d109164849ee6d6500d46469de

core/java/android/annotation/SystemApi.java

@@ -44,9 +44,24 @@ public @interface SystemApi {
     enum Client {
         /**
          * Specifies that the intended clients of a SystemApi are privileged apps.
-         * This is the default value for {@link #client}.
+         * This is the default value for {@link #client}. This implies
+         * MODULE_APPS and MODULE_LIBRARIES as well, which means that APIs will also
+         * be available to module apps and jars.
          */
         PRIVILEGED_APPS,
+
+        /**
+         * Specifies that the intended clients of a SystemApi are modules implemented
+         * as apps, like the NetworkStack app. This implies MODULE_LIBRARIES as well,
+         * which means that APIs will also be available to module jars.
+         */
+        MODULE_APPS,
+
+        /**
+         * Specifies that the intended clients of a SystemApi are modules implemented
+         * as libraries, like the conscrypt.jar in the conscrypt APEX.
+         */
+        MODULE_LIBRARIES
     }
 
     enum Process {
@@ -55,6 +70,11 @@ public @interface SystemApi {
          * This is the default value for {@link #process}.
          */
         ALL,
+
+        /**
+         * Specifies that the SystemAPI is available only in the system server process.
+         */
+        SYSTEM_SERVER
     }
 
     /**

services/Android.bp

@@ -110,7 +110,7 @@ droidstubs {
     srcs: [":services-sources"],
     installable: false,
     // TODO: remove the --hide options below
-    args: " --show-single-annotation android.annotation.SystemApi\\(client=android.annotation.SystemApi.Client.INTERNAL,process=android.annotation.SystemApi.Process.SYSTEM_SERVER\\)" +
+    args: " --show-single-annotation android.annotation.SystemApi\\(client=android.annotation.SystemApi.Client.MODULE_LIBRARIES,process=android.annotation.SystemApi.Process.SYSTEM_SERVER\\)" +
         " --hide-annotation android.annotation.Hide" +
         " --hide-package com.google.android.startop.iorap" +
         " --hide ReferencesHidden" +