Ensure user is unlocked before binding to KeyChain service

This stops KeyChain from throwing AssertionError when binding to
service fails due to user being locked, which would have crashed
the entire system server.

Bug: 149912024
Test: atest KeyChainTests
Change-Id: Ie110a4210e157cc9b111d845478bdf21e948ba4f

keystore/java/android/security/KeyChain.java

@@ -34,6 +34,7 @@ import android.os.Looper;
 import android.os.Process;
 import android.os.RemoteException;
 import android.os.UserHandle;
+import android.os.UserManager;
 import android.security.keystore.AndroidKeyStoreProvider;
 import android.security.keystore.KeyPermanentlyInvalidatedException;
 import android.security.keystore.KeyProperties;
@@ -811,6 +812,10 @@ public final class KeyChain {
             throw new NullPointerException("context == null");
         }
         ensureNotOnMainThread(context);
+        if (!UserManager.get(context).isUserUnlocked(user)) {
+            throw new IllegalStateException("User must be unlocked");
+        }
+
         final CountDownLatch countDownLatch = new CountDownLatch(1);
         final AtomicReference<IKeyChainService> keyChainService = new AtomicReference<>();
         ServiceConnection keyChainServiceConnection = new ServiceConnection() {