Convert the rest of chrome_public_test_apk InstrumentationTestCases to JUnit4

chrome/android/javatests/src/org/chromium/chrome/browser/webapps/WebappAuthenticatorTest.java

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.webapps;
 
 import android.content.Context;
+import android.support.test.InstrumentationRegistry;
 import android.support.test.filters.SmallTest;
-import android.test.InstrumentationTestCase;
+
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
 
 import org.chromium.base.metrics.RecordHistogram;
 import org.chromium.base.test.util.Feature;
+import org.chromium.chrome.test.ChromeJUnit4ClassRunner;
 
 /**
  * Tests for {@link WebappAuthenticator}.
  */
-public class WebappAuthenticatorTest extends InstrumentationTestCase {
-    @Override
+@RunWith(ChromeJUnit4ClassRunner.class)
+public class WebappAuthenticatorTest {
+    @Before
     public void setUp() throws Exception {
-        super.setUp();
         RecordHistogram.setDisabledForTests(true);
     }
 
-    @Override
-    protected void tearDown() throws Exception {
-        super.tearDown();
+    @After
+    public void tearDown() throws Exception {
         RecordHistogram.setDisabledForTests(false);
     }
 
+    @Test
     @SmallTest
     @Feature({"Webapps"})
     public void testAuthentication() {
-        Context context = getInstrumentation().getTargetContext();
+        Context context = InstrumentationRegistry.getInstrumentation().getTargetContext();
         String url = "http://www.example.org/hello.html";
         byte[] mac = WebappAuthenticator.getMacForUrl(context, url);
-        assertNotNull(mac);
-        assertTrue(WebappAuthenticator.isUrlValid(context, url, mac));
-        assertFalse(WebappAuthenticator.isUrlValid(context, url + "?goats=true", mac));
+        Assert.assertNotNull(mac);
+        Assert.assertTrue(WebappAuthenticator.isUrlValid(context, url, mac));
+        Assert.assertFalse(WebappAuthenticator.isUrlValid(context, url + "?goats=true", mac));
         mac[4] += (byte) 1;
-        assertFalse(WebappAuthenticator.isUrlValid(context, url, mac));
+        Assert.assertFalse(WebappAuthenticator.isUrlValid(context, url, mac));
     }
 }