[Cronet] Change interface APIs to abstract classes

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

 // Copyright 2014 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 android.os.ConditionVariable;
 import android.test.suitebuilder.annotation.SmallTest;
 import android.util.Pair;
 
@@ skipping 1340 matching lines @@
         // but request will be destroyed from network thread.
         requestDestroyed.block();
 
         assertFalse(listener.isDone());
         assertTrue(urlRequest.isDone());
     }
 
     @SmallTest
     @Feature({"Cronet"})
     public void testUploadExecutorShutdown() throws Exception {
-        class HangingUploadDataProvider implements UploadDataProvider {
+        class HangingUploadDataProvider extends UploadDataProvider {
             UploadDataSink mUploadDataSink;
             ByteBuffer mByteBuffer;
             ConditionVariable mReadCalled = new ConditionVariable(false);
 
             @Override
             public long getLength() {
                 return 69;
             }
 
             @Override
@@ skipping 40 matching lines @@
             int end) {
         // Use a duplicate to avoid modifying byteBuffer.
         ByteBuffer duplicate = byteBuffer.duplicate();
         duplicate.position(start);
         duplicate.limit(end);
         byte[] contents = new byte[duplicate.remaining()];
         duplicate.get(contents);
         return new String(contents);
     }
 }