[Cronet] Change interface APIs to abstract classes

components/cronet/android/java/src/org/chromium/net/urlconnection/CronetHttpURLConnection.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.urlconnection;
 
 import android.util.Pair;
 
 import org.chromium.base.Log;
 import org.chromium.net.ExtendedResponseInfo;
 import org.chromium.net.ResponseInfo;
-import org.chromium.net.UploadDataProvider;
 import org.chromium.net.UrlRequest;
 import org.chromium.net.UrlRequestContext;
 import org.chromium.net.UrlRequestException;
 import org.chromium.net.UrlRequestListener;
 
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.net.HttpURLConnection;
@@ skipping 228 matching lines @@
 
     /**
      * Starts the request if {@code connected} is false.
      */
     private void startRequest() throws IOException {
         if (connected) {
             return;
         }
         if (doOutput) {
             if (mOutputStream != null) {
-                mRequest.setUploadDataProvider(
-                        (UploadDataProvider) mOutputStream, mMessageLoop);
+                mRequest.setUploadDataProvider(mOutputStream.getUploadDataProvider(), mMessageLoop);
                 if (getRequestProperty(CONTENT_LENGTH) == null && !isChunkedUpload()) {
                     addRequestProperty(CONTENT_LENGTH,
-                            Long.toString(((UploadDataProvider) mOutputStream).getLength()));
+                            Long.toString(mOutputStream.getUploadDataProvider().getLength()));
                 }
                 // Tells mOutputStream that startRequest() has been called, so
                 // the underlying implementation can prepare for reading if needed.
                 mOutputStream.setConnected();
             } else {
                 if (getRequestProperty(CONTENT_LENGTH) == null) {
                     addRequestProperty(CONTENT_LENGTH, "0");
                 }
             }
             // Default Content-Type to application/x-www-form-urlencoded
@@ skipping 135 matching lines @@
     private int findRequestProperty(String key) {
         for (int i = 0; i < mRequestHeaders.size(); i++) {
             Pair<String, String> entry = mRequestHeaders.get(i);
             if (entry.first.equalsIgnoreCase(key)) {
                 return i;
             }
         }
         return -1;
     }
 
-    private class CronetUrlRequestListener implements UrlRequestListener {
+    private class CronetUrlRequestListener extends UrlRequestListener {
         public CronetUrlRequestListener() {
         }
 
         @Override
         public void onResponseStarted(UrlRequest request, ResponseInfo info) {
             mResponseInfo = info;
             // Quits the message loop since we have the headers now.
             mMessageLoop.quit();
         }
 
@@ skipping 106 matching lines @@
     }
 
     /**
      * Returns whether the client has used {@link #setChunkedStreamingMode} to
      * set chunked encoding for upload.
      */
     private boolean isChunkedUpload() {
         return chunkLength > 0;
     }
 }