Move Android Keystore impl to android.security.keystore.

This moves the non-public API classes backing Android Keystore from
android.security to android.security.keystore, a package specially
created for Android Keystore.

Bug: 18088752
Change-Id: Ibf04d6a26c54d310b0501fc5e34f37b1176324ad
diff --git a/keystore/java/android/security/Credentials.java b/keystore/java/android/security/Credentials.java
index 6283e02..5d777b0 100644
--- a/keystore/java/android/security/Credentials.java
+++ b/keystore/java/android/security/Credentials.java
@@ -216,7 +216,7 @@
      * particular {@code alias}. All three can exist for any given alias.
      * Returns {@code true} if there was at least one of those types.
      */
-    static boolean deleteAllTypesForAlias(KeyStore keystore, String alias) {
+    public static boolean deleteAllTypesForAlias(KeyStore keystore, String alias) {
         /*
          * Make sure every type is deleted. There can be all three types, so
          * don't use a conditional here.
@@ -231,7 +231,7 @@
      * particular {@code alias}. All three can exist for any given alias.
      * Returns {@code true} if there was at least one of those types.
      */
-    static boolean deleteCertificateTypesForAlias(KeyStore keystore, String alias) {
+    public static boolean deleteCertificateTypesForAlias(KeyStore keystore, String alias) {
         /*
          * Make sure every certificate type is deleted. There can be two types,
          * so don't use a conditional here.
@@ -252,7 +252,7 @@
      * Delete secret key for a particular {@code alias}.
      * Returns {@code true} if an entry was was deleted.
      */
-    static boolean deleteSecretKeyTypeForAlias(KeyStore keystore, String alias) {
+    public static boolean deleteSecretKeyTypeForAlias(KeyStore keystore, String alias) {
         return keystore.delete(Credentials.USER_SECRET_KEY + alias);
     }
 }