Convert the rest of chrome_public_test_apk InstrumentationTestCases to JUnit4

chrome/android/javatests/src/org/chromium/chrome/browser/download/DownloadUtilsTest.java

 // Copyright 2017 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.download;
 
 import android.support.test.filters.SmallTest;
-import android.test.InstrumentationTestCase;
+
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.runner.RunWith;
 
 import org.chromium.base.test.util.Feature;
+import org.chromium.chrome.test.ChromeJUnit4ClassRunner;
 
 /**
  * Tests of {@link DownloadUtils}.
  */
-public class DownloadUtilsTest extends InstrumentationTestCase {
+@RunWith(ChromeJUnit4ClassRunner.class)
+public class DownloadUtilsTest {
     /**
      * Test {@link DownloadUtils#getAbbrieviatedFileName()} method.
      */
+    @Test
     @SmallTest
     @Feature({"Download"})
     public void testGetAbbrieviatedFileName() {
-        assertEquals("123.pdf", DownloadUtils.getAbbreviatedFileName("123.pdf", 10));
-        assertEquals("1" + DownloadUtils.ELLIPSIS,
-                DownloadUtils.getAbbreviatedFileName("123.pdf", 1));
-        assertEquals("12" + DownloadUtils.ELLIPSIS,
-                DownloadUtils.getAbbreviatedFileName("1234567", 2));
-        assertEquals("123" + DownloadUtils.ELLIPSIS + ".pdf",
+        Assert.assertEquals("123.pdf", DownloadUtils.getAbbreviatedFileName("123.pdf", 10));
+        Assert.assertEquals(
+                "1" + DownloadUtils.ELLIPSIS, DownloadUtils.getAbbreviatedFileName("123.pdf", 1));
+        Assert.assertEquals(
+                "12" + DownloadUtils.ELLIPSIS, DownloadUtils.getAbbreviatedFileName("1234567", 2));
+        Assert.assertEquals("123" + DownloadUtils.ELLIPSIS + ".pdf",
                 DownloadUtils.getAbbreviatedFileName("1234567.pdf", 7));
     }
 }