Add keystore API for metrics re-routing.

Keystore2 atoms need to be routed to statsd via a proxy.
The proxy needs to call this API in order to pull metrics from
keystore.

Bug: 188590587
Test: Statsd Testdrive script
Merged-In: I28f8675fe5467b0760418c4d2d87808e45657be1

Change-Id: I28f8675fe5467b0760418c4d2d87808e45657be1
diff --git a/keystore2/aidl/Android.bp b/keystore2/aidl/Android.bp
index 5e4e22c..5416024 100644
--- a/keystore2/aidl/Android.bp
+++ b/keystore2/aidl/Android.bp
@@ -169,3 +169,25 @@
     },
 }
 
+aidl_interface {
+    name: "android.security.metrics",
+    srcs: [ "android/security/metrics/*.aidl" ],
+    imports: [
+        "android.system.keystore2-V1",
+    ],
+    unstable: true,
+    backend: {
+        java: {
+            platform_apis: true,
+            srcs_available: true,
+        },
+        rust: {
+            enabled: true,
+        },
+        ndk: {
+            enabled: true,
+            apps_enabled: false,
+        }
+    },
+}
+