Keystore 2.0: Add convenience API for watchdog module.

Also make use of watchdog toggleable with a feature flag.

Test: N/A
Change-Id: Ibdd14de09bfb31067313373805475a8998fd1c00
diff --git a/keystore2/Android.bp b/keystore2/Android.bp
index 8d0f4e7..b7270b1 100644
--- a/keystore2/Android.bp
+++ b/keystore2/Android.bp
@@ -62,6 +62,9 @@
     shared_libs: [
         "libcutils",
     ],
+    features: [
+        "watchdog",
+    ],
 }
 
 rust_library {
@@ -91,6 +94,10 @@
         "libkeystore2_test_utils",
         "libnix",
     ],
+    // The test should always include watchdog.
+    features: [
+        "watchdog",
+    ],
 }
 
 rust_binary {