Add default implementation of experimental methods

components/cronet/android/java/src/org/chromium/net/impl/JavaCronetEngine.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.impl;
 
 import static android.os.Process.THREAD_PRIORITY_BACKGROUND;
 import static android.os.Process.THREAD_PRIORITY_MORE_FAVORABLE;
 
 import org.chromium.net.BidirectionalStream;
-import org.chromium.net.EffectiveConnectionType;
 import org.chromium.net.ExperimentalBidirectionalStream;
 import org.chromium.net.NetworkQualityRttListener;
 import org.chromium.net.NetworkQualityThroughputListener;
 import org.chromium.net.RequestFinishedInfo;
-import org.chromium.net.RttThroughputValues;
 import org.chromium.net.UrlRequest;
 
 import java.io.IOException;
 import java.net.Proxy;
 import java.net.URL;
 import java.net.URLConnection;
 import java.net.URLStreamHandler;
 import java.net.URLStreamHandlerFactory;
 import java.util.Collection;
 import java.util.List;
@@ skipping 86 matching lines @@
         return "";
     }
 
     @Override
     public byte[] getGlobalMetricsDeltas() {
         return new byte[0];
     }
 
     @Override
     public int getEffectiveConnectionType() {
-        return EffectiveConnectionType.TYPE_UNKNOWN;
+        return EFFECTIVE_CONNECTION_TYPE_UNKNOWN;
     }
 
     @Override
     public int getHttpRttMs() {
-        return RttThroughputValues.INVALID_RTT_THROUGHPUT;
+        return CONNECTION_METRIC_UNKNOWN;
     }
 
     @Override
     public int getTransportRttMs() {
-        return RttThroughputValues.INVALID_RTT_THROUGHPUT;
+        return CONNECTION_METRIC_UNKNOWN;
     }
 
     @Override
     public int getDownstreamThroughputKbps() {
-        return RttThroughputValues.INVALID_RTT_THROUGHPUT;
+        return CONNECTION_METRIC_UNKNOWN;
     }
 
     @Override
     public void configureNetworkQualityEstimatorForTesting(
             boolean useLocalHostRequests, boolean useSmallerResponses) {}
 
     @Override
     public void addRttListener(NetworkQualityRttListener listener) {}
 
     @Override
@@ skipping 26 matching lines @@
         // Returning null causes this factory to pass though, which ends up using the platform's
         // implementation.
         return new URLStreamHandlerFactory() {
             @Override
             public URLStreamHandler createURLStreamHandler(String protocol) {
                 return null;
             }
         };
     }
 }