[Cronet] Add callback wrapper classes to enforce API version checking.

components/cronet/android/java/src/org/chromium/net/impl/UrlResponseInfoImpl.java

 // Copyright 2016 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.impl;
 
 import org.chromium.net.UrlResponseInfo;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ skipping 11 matching lines @@
  * redirect response.
  */
 public final class UrlResponseInfoImpl extends UrlResponseInfo {
     private final List<String> mResponseInfoUrlChain;
     private final int mHttpStatusCode;
     private final String mHttpStatusText;
     private final boolean mWasCached;
     private final String mNegotiatedProtocol;
     private final String mProxyServer;
     private final AtomicLong mReceivedBytesCount;
-    private final HeaderBlock mHeaders;
+    private final HeaderBlockImpl mHeaders;
 
     /**
      * Unmodifiable container of response headers or trailers.
      */
     public static final class HeaderBlockImpl extends HeaderBlock {
         private final List<Map.Entry<String, String>> mAllHeadersList;
         private Map<String, List<String>> mHeadersMap;
 
         HeaderBlockImpl(List<Map.Entry<String, String>> allHeadersList) {
             mAllHeadersList = allHeadersList;
@@ skipping 112 matching lines @@
                 getProxyServer(), getReceivedBytesCount());
     }
 
     /**
      * Sets mReceivedBytesCount. Must not be called after request completion or cancellation.
      */
     public void setReceivedBytesCount(long currentReceivedBytesCount) {
         mReceivedBytesCount.set(currentReceivedBytesCount);
     }
 }