Make NQE a derived class of NetworkQualityProvider

net/nqe/rtt_throughput_estimates_observer.h

Index: net/nqe/rtt_throughput_estimates_observer.h
diff --git a/net/nqe/rtt_throughput_estimates_observer.h b/net/nqe/rtt_throughput_estimates_observer.h
new file mode 100644
index 0000000000000000000000000000000000000000..26c77bcb4cf9d7f9114ee1564bbbca47bec4e245
--- /dev/null
+++ b/net/nqe/rtt_throughput_estimates_observer.h
@@ -0,0 +1,48 @@
+// Copyright 2017 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.
+
+#ifndef NET_NQE_NETWORK_QUALITY_RTT_THROUGHPUT_ESTIMATES_OBSERVER_H_
+#define NET_NQE_NETWORK_QUALITY_RTT_THROUGHPUT_ESTIMATES_OBSERVER_H_
+
+#include <stdint.h>
+
+#include "base/compiler_specific.h"
+#include "base/macros.h"
+#include "base/time/time.h"
+#include "net/base/net_export.h"
+
+namespace net {
+
+// Observes changes in the network quality.
+class NET_EXPORT RTTAndThroughputEstimatesObserver {
+ public:
+  // Notifies the observer when estimated HTTP RTT, estimated transport RTT or
+  // estimated downstream throughput is computed. NetworkQualityEstimator
+  // computes the RTT and throughput estimates at regular intervals.
+  // Additionally, when there is a change in the connection type of the
+  // device, then the estimates are immediately computed.
+  //
+  // |http_rtt|, |transport_rtt| and |downstream_throughput_kbps| are the
+  // computed estimates of the HTTP RTT, transport RTT and downstream
+  // throughput (in kilobits per second), respectively. If an estimate of the
+  // HTTP or transport RTT is unavailable, it will be set to
+  // nqe::internal::InvalidRTT(). If the throughput estimate is unavailable,
+  // it will be set to nqe::internal::kInvalidThroughput.
+  virtual void OnRTTOrThroughputEstimatesComputed(
+      base::TimeDelta http_rtt,
+      base::TimeDelta transport_rtt,
+      int32_t downstream_throughput_kbps) = 0;
+
+  virtual ~RTTAndThroughputEstimatesObserver() {}
+
+ protected:
+  RTTAndThroughputEstimatesObserver() {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(RTTAndThroughputEstimatesObserver);
+};
+
+}  // namespace net
+
+#endif  // NET_NQE_NETWORK_QUALITY_RTT_THROUGHPUT_ESTIMATES_OBSERVER_H_