Switch frameworks/base over from @hidden Charsets to public StandardCharsets.

Bug: 3484927
Change-Id: I5d136d2ee629588538602766a182ae14ce5fc63c
diff --git a/keystore/tests/src/android/security/KeyStoreTest.java b/keystore/tests/src/android/security/KeyStoreTest.java
index 1de1eaf..0f29800 100644
--- a/keystore/tests/src/android/security/KeyStoreTest.java
+++ b/keystore/tests/src/android/security/KeyStoreTest.java
@@ -22,7 +22,7 @@
 import android.test.ActivityUnitTestCase;
 import android.test.AssertionFailedError;
 import android.test.suitebuilder.annotation.MediumTest;
-import java.nio.charset.Charsets;
+import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.Date;
 import java.util.HashSet;
@@ -45,11 +45,11 @@
     private static final String TEST_KEYNAME = "test-key";
     private static final String TEST_KEYNAME1 = "test-key.1";
     private static final String TEST_KEYNAME2 = "test-key\02";
-    private static final byte[] TEST_KEYVALUE = "test value".getBytes(Charsets.UTF_8);
+    private static final byte[] TEST_KEYVALUE = "test value".getBytes(StandardCharsets.UTF_8);
 
     // "Hello, World" in Chinese
     private static final String TEST_I18N_KEY = "\u4F60\u597D, \u4E16\u754C";
-    private static final byte[] TEST_I18N_VALUE = TEST_I18N_KEY.getBytes(Charsets.UTF_8);
+    private static final byte[] TEST_I18N_VALUE = TEST_I18N_KEY.getBytes(StandardCharsets.UTF_8);
 
     // Test vector data for signatures
     private static final byte[] TEST_DATA =  new byte[256];