Replace Base64Encoder with Base64Utils

Replace the custom Base64Encoder class with Spring's Base64Utils which
since 4.2 can encode bytes using Java 8's encoder, commons-digest or
Java 6's JAX-B encoder.

Closes gh-4189

spring-boot-devtools/src/test/java/org/springframework/boot/devtools/livereload/Base64EncoderTests.java

@@ -1,53 +0,0 @@
-/*
- * Copyright 2012-2015 the original author or authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.springframework.boot.devtools.livereload;
-
-import org.junit.Test;
-
-import static org.hamcrest.Matchers.equalTo;
-import static org.junit.Assert.assertThat;
-
-/**
- * Tests for {@link Base64Encoder}.
- *
- * @author Phillip Webb
- */
-public class Base64EncoderTests {
-
-	private static final String TEXT = "Man is distinguished, not only by his reason, "
-			+ "but by this singular passion from other animals, which is a lust of the "
-			+ "mind, that by a perseverance of delight in the continued and indefatigable "
-			+ "generation of knowledge, exceeds the short vehemence of any carnal pleasure.";
-
-	private static final String ENCODED = "TWFuIGlzIGRpc3Rpbmd1aXNoZWQsIG5vdCBvbmx5IGJ5I"
-			+ "GhpcyByZWFzb24sIGJ1dCBieSB0aGlzIHNpbmd1bGFyIHBhc3Npb24gZnJvbSBvdGhlciBhbm"
-			+ "ltYWxzLCB3aGljaCBpcyBhIGx1c3Qgb2YgdGhlIG1pbmQsIHRoYXQgYnkgYSBwZXJzZXZlcmF"
-			+ "uY2Ugb2YgZGVsaWdodCBpbiB0aGUgY29udGludWVkIGFuZCBpbmRlZmF0aWdhYmxlIGdlbmVy"
-			+ "YXRpb24gb2Yga25vd2xlZGdlLCBleGNlZWRzIHRoZSBzaG9ydCB2ZWhlbWVuY2Ugb2YgYW55I"
-			+ "GNhcm5hbCBwbGVhc3VyZS4=";
-
-	@Test
-	public void encodeText() {
-		assertThat(Base64Encoder.encode(TEXT), equalTo(ENCODED));
-		assertThat(Base64Encoder.encode("pleasure."), equalTo("cGxlYXN1cmUu"));
-		assertThat(Base64Encoder.encode("leasure."), equalTo("bGVhc3VyZS4="));
-		assertThat(Base64Encoder.encode("easure."), equalTo("ZWFzdXJlLg=="));
-		assertThat(Base64Encoder.encode("asure."), equalTo("YXN1cmUu"));
-		assertThat(Base64Encoder.encode("sure."), equalTo("c3VyZS4="));
-	}
-
-}