Allow posting the CronetEngine UI Thread initialization on a custom Ui executor instead of the defa…

components/cronet/android/api/src/org/chromium/net/ExperimentalCronetEngine.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;
 
 import android.content.Context;
 import android.support.annotation.VisibleForTesting;
 
 import java.io.IOException;
 import java.net.Proxy;
@@ skipping 193 matching lines @@
             return this;
         }
 
         @Override
         public Builder setLibraryLoader(LibraryLoader loader) {
             super.setLibraryLoader(loader);
             return this;
         }
 
         @Override
+        public Builder setUiThreadExecutor(Executor uiExecutor) {
+            super.setUiThreadExecutor(uiExecutor);
+            return this;
+        }
+
+        @Override
         public Builder enableQuic(boolean value) {
             super.enableQuic(value);
             return this;
         }
 
         @Override
         public Builder enableHttp2(boolean value) {
             super.enableHttp2(value);
             return this;
         }
@@ skipping 218 matching lines @@
      * {@link #CONNECTION_METRIC_UNKNOWN} if the value is
      * unavailable. This must be called after
      * {@link Builder#enableNetworkQualityEstimator}, and will
      * throw an exception otherwise.
      * @return Estimate of the downstream throughput in kilobits per second.
      */
     public int getDownstreamThroughputKbps() {
         return CONNECTION_METRIC_UNKNOWN;
     }
 }