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.

[mef, 2015/08/28 20:53:16]

Maybe add comment that this is called on network thread and should NOT be doing
anything lengthy?

[bengr, 2015/08/28 23:51:36]

Done.

+     * @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, int whenMs, int source);
+}