Update AppRTCMobile tests to use JUnit4.

webrtc/examples/androidtests/src/org/appspot/apprtc/test/VideoFileRendererTest.java

 /*
  *  Copyright 2016 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 package org.webrtc;
 
-import android.test.InstrumentationTestCase;
-import android.test.suitebuilder.annotation.SmallTest;
+import static org.junit.Assert.assertEquals;
 
+import android.support.test.filters.SmallTest;
 import java.io.File;
 import java.io.IOException;
 import java.io.RandomAccessFile;
 import java.lang.Thread;
+import java.nio.ByteBuffer;
 import java.nio.charset.StandardCharsets;
-import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.Random;
+import org.chromium.base.test.BaseJUnit4ClassRunner;
+import org.junit.Test;
+import org.junit.runner.RunWith;
 
-public class VideoFileRendererTest extends InstrumentationTestCase {
+@RunWith(BaseJUnit4ClassRunner.class)
+public class VideoFileRendererTest {
+  @Test
   @SmallTest
   public void testYuvRenderingToFile() throws InterruptedException, IOException {
     EglBase eglBase = EglBase.create();
     final String videoOutPath = "/sdcard/chromium_tests_root/testvideoout.y4m";
     int frameWidth = 4;
     int frameHeight = 4;
     VideoFileRenderer videoFileRenderer =
         new VideoFileRenderer(videoOutPath, frameWidth, frameHeight, eglBase.getEglBaseContext());
 
     String[] frames = {
@@ skipping 33 matching lines @@
           + "THE SECOND FRAME qwerty.FRAME\n"
           + "HERE IS THE THRID FRAME!";
       assertEquals(expected, fileContent);
     } finally {
       writtenFile.close();
     }
 
     new File(videoOutPath).delete();
   }
 }