[Cronet] Change interface APIs to abstract classes

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

 // Copyright 2015 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.net;
 
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.concurrent.Executor;
 
 /**
  * An UploadDataProvider implementation used in tests.
  */
-class TestUploadDataProvider implements UploadDataProvider {
+class TestUploadDataProvider extends UploadDataProvider {
     // Indicates whether all success callbacks are synchronous or asynchronous.
     // Doesn't apply to errors.
     enum SuccessCallbackMode {
         SYNC,
         ASYNC
     };
 
     // Indicates whether failures should throw exceptions, invoke callbacks
     // synchronously, or invoke callback asynchronously.
     enum FailMode {
@@ skipping 209 matching lines @@
                                 "Async rewind failure"));
                     }
                 };
                 mExecutor.execute(errorRunnable);
                 return true;
             default:
                 return false;
         }
     }
 }