Make NQE a derived class of NetworkQualityProvider

net/nqe/effective_connection_type_observer.h

Index: net/nqe/effective_connection_type_observer.h
diff --git a/net/nqe/effective_connection_type_observer.h b/net/nqe/effective_connection_type_observer.h
new file mode 100644
index 0000000000000000000000000000000000000000..dd3c05d10807b400c3d9c9c715e2cbaa21213f26
--- /dev/null
+++ b/net/nqe/effective_connection_type_observer.h
@@ -0,0 +1,43 @@
+// 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_EFFECTIVE_CONNECTION_TYPE_OBSERVER_H_
+#define NET_NQE_NETWORK_QUALITY_EFFECTIVE_CONNECTION_TYPE_OBSERVER_H_
+
+#include "base/compiler_specific.h"
+#include "base/gtest_prod_util.h"
+#include "base/macros.h"
+#include "net/nqe/effective_connection_type.h"
+
+namespace net {
+
+// Observes changes in effective connection type.
+class NET_EXPORT EffectiveConnectionTypeObserver {
+ public:
+  // Notifies the observer of a change in the effective connection type.
+  // NetworkQualityEstimator computes the effective connection type once in
+  // every interval of duration
+  // |effective_connection_type_recomputation_interval_|. Additionally, when
+  // there is a change in the connection type of the device, then the
+  // effective connection type is immediately recomputed. The observer must
+  // register and unregister itself on the IO thread. All the observers would
+  // be notified on the IO thread.

[RyanSturm, 2017/06/05 21:21:02]

Remove parts about IO thread? That should be commented in the observer owner not
the observer interface (in case we want to use it on the UI thread.

[tbansal1, 2017/06/06 16:55:50]

Done.

+  //
+  // If the computed effective connection type is different from the
+  // previously notified effective connection type, then all the registered
+  // observers are notified of the new effective connection type.
+  virtual void OnEffectiveConnectionTypeChanged(
+      EffectiveConnectionType type) = 0;
+
+ protected:
+  EffectiveConnectionTypeObserver() {}
+  virtual ~EffectiveConnectionTypeObserver() {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(EffectiveConnectionTypeObserver);
+};
+
+}  // namespace net
+
+#endif  // NET_NQE_NETWORK_QUALITY_EFFECTIVE_CONNECTION_TYPE_OBSERVER_H_