[Cronet] Add new API methods before removing old ones

components/cronet/android/api/src/org/chromium/net/CronetEngine.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.content.Context;
 import android.net.http.HttpResponseCache;
 import android.support.annotation.IntDef;
@@ skipping 1136 matching lines @@
     public abstract void addRequestFinishedListener(RequestFinishedInfo.Listener listener);
 
     /**
      * Removes a finished request listener.
      *
      * @param listener the listener to remove.
      *
      * @hide it's a prototype.
      */
     public abstract void removeRequestFinishedListener(RequestFinishedInfo.Listener listener);
+
+    /**
+     * Creates a builder for {@link UrlRequest}. All callbacks formatted
+     * generated {@link UrlRequest} objects will be invoked on
+     * {@code executor}'s threads. {@code executor} must not run tasks on the
+     * thread calling {@link Executor#execute} to prevent blocking networking
+     * operations and causing exceptions during shutdown.
+     *
+     * @param url URL for the generated requests.
+     * @param callback callback object that gets invoked on different events.
+     * @param executor {@link Executor} on which all callbacks will be invoked.
+     */
+    public UrlRequest.Builder newUrlRequestBuilder(
+            String url, UrlRequest.Callback callback, Executor executor) {
+        return new UrlRequest.Builder(url, callback, executor, this);
+    }
 }