[Cronet] Change interface APIs to abstract classes

components/cronet/android/test/javaperftests/src/org/chromium/net/CronetPerfTestActivity.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 android.annotation.SuppressLint;
 import android.app.Activity;
 import android.net.Uri;
 import android.os.AsyncTask;
@@ skipping 334 matching lines @@
                 };
                 final UrlRequest request = mCronetContext.createRequest(mUrl.toString(),
                         new Listener(buffer, completionCallback), mWorkQueueExecutor);
                 if (mDirection == Direction.UP) {
                     request.setUploadDataProvider(new Uploader(buffer), mWorkQueueExecutor);
                     request.addHeader("Content-Type", "application/octet-stream");
                 }
                 request.start();
             }
 
-            private class Uploader implements UploadDataProvider {
+            private class Uploader extends UploadDataProvider {
                 private final ByteBuffer mBuffer;
                 private int mRemainingBytes;
 
                 Uploader(ByteBuffer buffer) {
                     mBuffer = buffer;
                     mRemainingBytes = mLength;
                 }
 
                 public long getLength() {
                     return mLength;
@@ skipping 12 matching lines @@
                     byteBuffer.put(mBuffer);
                     mRemainingBytes -= mBuffer.position();
                     uploadDataSink.onReadSucceeded(false);
                 }
 
                 public void rewind(UploadDataSink uploadDataSink) {
                     uploadDataSink.onRewindError(new Exception("no rewinding"));
                 }
             }
 
-            private class Listener implements UrlRequestListener {
+            private class Listener extends UrlRequestListener {
                 private final ByteBuffer mBuffer;
                 private final Runnable mCompletionCallback;
 
                 Listener(ByteBuffer buffer, Runnable completionCallback) {
                     mBuffer = buffer;
                     mCompletionCallback = completionCallback;
                 }
 
                 @Override
                 public void onResponseStarted(UrlRequest request, ResponseInfo info) {
@@ skipping 187 matching lines @@
     }
 
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         mConfig = getIntent().getData();
         // Execute benchmarks on another thread to avoid networking on main thread.
         new BenchmarkTask().execute();
     }
 }