Fix org.mockito.Matchers deprecation warnings in DirectRTCClientTest.

ArgumentMatchers is the new name of the class. Also, we don't need to
pass a class to the isNotNull matcher.

BUG=webrtc:6558
R=magjed@webrtc.org

Review-Url: https://codereview.webrtc.org/2440433002
Cr-Commit-Position: refs/heads/master@{#14706}
diff --git a/webrtc/examples/androidjunit/src/org/appspot/apprtc/DirectRTCClientTest.java b/webrtc/examples/androidjunit/src/org/appspot/apprtc/DirectRTCClientTest.java
index 6079fc6..2da8164 100644
--- a/webrtc/examples/androidjunit/src/org/appspot/apprtc/DirectRTCClientTest.java
+++ b/webrtc/examples/androidjunit/src/org/appspot/apprtc/DirectRTCClientTest.java
@@ -13,8 +13,8 @@
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
-import static org.mockito.Matchers.any;
-import static org.mockito.Matchers.isNotNull;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.isNotNull;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.timeout;
 import static org.mockito.Mockito.verify;
@@ -110,6 +110,8 @@
     }
   }
 
+  // TODO(sakal): Replace isNotNull(class) with isNotNull() once Java 8 is used.
+  @SuppressWarnings("deprecation")
   @Test
   public void testDirectRTCClient() {
     server.connectToRoom(new AppRTCClient.RoomConnectionParameters(ROOM_URL, "0.0.0.0", LOOPBACK));