Revert "Expose getSpi from crypto operations as hidden API."

This reverts commit 050e672aaaaa8f8c57788e8d551f43c5fbffe339.

The users of public getSpi have been migrated to getCurrentSpi
introduced in 5d15925a79b8beddfafa8de2ede7fff360a386cb.

(cherry-picked from commit c52bf74f7e53b9f58bbeb29f4d248e7dba7d15ce)

Bug: 18088752
Change-Id: Ied72c8a62a49d9fba8b7bc2d3ef2e30da7daa6e4
diff --git a/luni/src/main/java/java/security/Signature.java b/luni/src/main/java/java/security/Signature.java
index a45fa59..795ccad 100644
--- a/luni/src/main/java/java/security/Signature.java
+++ b/luni/src/main/java/java/security/Signature.java
@@ -245,15 +245,6 @@
     }
 
     /**
-     * Gets the SPI implementation backing this signature.
-     *
-     * @hide
-     */
-    public SignatureSpi getSpi() {
-        return null;
-    }
-
-    /**
      * Returns the {@code SignatureSpi} backing this {@code Signature} or {@code null} if no
      * {@code SignatureSpi} is backing this {@code Signature}.
      *
@@ -749,11 +740,8 @@
 
         /**
          * Convenience call when the Key is not available.
-         *
-         * @hide
          */
-        @Override
-        public SignatureSpi getSpi() {
+        private SignatureSpi getSpi() {
             return getSpi(null);
         }
 
diff --git a/luni/src/main/java/javax/crypto/Cipher.java b/luni/src/main/java/javax/crypto/Cipher.java
index 225822d..5a66c20 100644
--- a/luni/src/main/java/javax/crypto/Cipher.java
+++ b/luni/src/main/java/javax/crypto/Cipher.java
@@ -366,10 +366,8 @@
 
     /**
      * Convenience call when the Key is not available.
-     *
-     * @hide
      */
-    public CipherSpi getSpi() {
+    private CipherSpi getSpi() {
         return getSpi(null);
     }
 
diff --git a/luni/src/main/java/javax/crypto/KeyAgreement.java b/luni/src/main/java/javax/crypto/KeyAgreement.java
index c804273..1ba660d 100644
--- a/luni/src/main/java/javax/crypto/KeyAgreement.java
+++ b/luni/src/main/java/javax/crypto/KeyAgreement.java
@@ -252,10 +252,8 @@
 
     /**
      * Convenience call when the Key is not available.
-     *
-     * @hide
      */
-    public KeyAgreementSpi getSpi() {
+    private KeyAgreementSpi getSpi() {
         return getSpi(null);
     }
 
diff --git a/luni/src/main/java/javax/crypto/Mac.java b/luni/src/main/java/javax/crypto/Mac.java
index 5774eb2..7da84e6 100644
--- a/luni/src/main/java/javax/crypto/Mac.java
+++ b/luni/src/main/java/javax/crypto/Mac.java
@@ -266,10 +266,8 @@
 
     /**
      * Convenience call when the Key is not available.
-     *
-     * @hide
      */
-    public MacSpi getSpi() {
+    private MacSpi getSpi() {
         return getSpi(null);
     }