[Cronet] Change interface APIs to abstract classes

components/cronet/android/test/javatests/src/org/chromium/net/TestUrlRequestListener.java

Index: components/cronet/android/test/javatests/src/org/chromium/net/TestUrlRequestListener.java
diff --git a/components/cronet/android/test/javatests/src/org/chromium/net/TestUrlRequestListener.java b/components/cronet/android/test/javatests/src/org/chromium/net/TestUrlRequestListener.java
index 85456dd799504919137932a21ca4e78a97cada7c..5ddd388610459ea0ba5229486df45447080c613c 100644
--- a/components/cronet/android/test/javatests/src/org/chromium/net/TestUrlRequestListener.java
+++ b/components/cronet/android/test/javatests/src/org/chromium/net/TestUrlRequestListener.java
@@ -23,7 +23,7 @@ import java.util.concurrent.ThreadFactory;
  * method to block thread until the request completes on another thread.
  * Allows to cancel, block request or throw an exception from an arbitrary step.
  */
-class TestUrlRequestListener implements UrlRequestListener {
+class TestUrlRequestListener extends UrlRequestListener {
     public ArrayList<ResponseInfo> mRedirectResponseInfoList =
             new ArrayList<ResponseInfo>();
     public ArrayList<String> mRedirectUrlList = new ArrayList<String>();