Respect QuicAllowed policy for new streams

chrome/browser/profiles/net_http_session_params_observer.h

+// 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 CHROME_BROWSER_PROFILES_NET_HTTP_SESSION_PARAMS_OBSERVER_H_
+#define CHROME_BROWSER_PROFILES_NET_HTTP_SESSION_PARAMS_OBSERVER_H_
+
+#include "base/callback_forward.h"
+#include "base/macros.h"
+#include "components/prefs/pref_member.h"
+
+class PrefService;
+
+namespace user_prefs {
+class PrefRegistrySyncable;
+}
+
+// Monitors network-related preferences for changes and applies them to
+// globally owned HttpNetworkSessions.
+// Profile-owned HttpNetworkSessions are taken care of by a
+// UpdateNetParamsCallback passed to the constructor.
+// The supplied PrefService must outlive this NetHttpSessionParamsObserver.
+// Must be used only on the UI thread.
+class NetHttpSessionParamsObserver {
+ public:
+  // Type of callback which will be called when QUIC is disabled. This
+  // callback will be called on the IO thread.
+  typedef base::Callback<void()> DisableQuicCallback;
+
+  // |prefs| must be non-NULL and |*prefs| must outlive this.
+  // |update_net_params_callback| will be invoked on the IO thread when an
+  // observed network parmeter is changed.
+  NetHttpSessionParamsObserver(PrefService* prefs,
+                               DisableQuicCallback disable_quic_callback);
+  ~NetHttpSessionParamsObserver();
+
+  // Register user preferences which NetHttpSessionParamsObserver uses into
+  // |registry|.
+  static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
+
+ private:
+  // Called on UI thread when an observed net pref changes
+  void ApplySettings();
+
+  BooleanPrefMember quic_allowed_;
+  DisableQuicCallback disable_quic_callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(NetHttpSessionParamsObserver);
+};
+
+#endif  // CHROME_BROWSER_PROFILES_NET_HTTP_SESSION_PARAMS_OBSERVER_H_