Added Network Quality Estimator Real-time interface to Cronet

components/cronet/android/java/src/org/chromium/net/NetworkQualityRttObserver.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;
+
+/**
+ * Interface to watch for observations of round trip times.
+ */
+public interface NetworkQualityRttObserver {
+    /**
+     * Reports a new round trip time observation. This is called on the network thread, so the
+     * observer should exit quickly.
+     * @param rttMs The round trip time in milliseconds.
+     * @param whenMs The time since the epoch in milliseconds.
+     * @param source The observation source from {@link NetworkQualityObservationSource}.
+     */
+    public void onRttObservation(int rttMs, long whenMs, int source);
+}