Respect QuicAllowed policy for new streams

chrome/browser/net/net_pref_observer.cc

Index: chrome/browser/net/net_pref_observer.cc
diff --git a/chrome/browser/net/net_pref_observer.cc b/chrome/browser/net/net_pref_observer.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3ae75408b183ff4ff69dae3356d7da429dd36e95
--- /dev/null
+++ b/chrome/browser/net/net_pref_observer.cc
@@ -0,0 +1,93 @@
+// Copyright (c) 2012 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.
+
+#include "chrome/browser/net/net_pref_observer.h"
+
+#include "base/bind.h"
+#include "base/command_line.h"
+#include "base/logging.h"
+#include "chrome/browser/browser_process.h"
+#include "chrome/browser/io_thread.h"
+#include "chrome/browser/profiles/profile_manager.h"
+#include "chrome/browser/safe_browsing/safe_browsing_service.h"
+#include "chrome/common/chrome_switches.h"
+#include "chrome/common/pref_names.h"
+#include "components/pref_registry/pref_registry_syncable.h"
+#include "components/prefs/pref_service.h"
+#include "content/public/browser/browser_thread.h"
+
+#include "net/http/http_network_session.h"
+
+using content::BrowserThread;
+
+NetPrefObserver::NetPrefObserver(
+    PrefService* prefs,
+    UpdateNetParamsCallback update_net_params_callback)
+    : update_net_params_callback_(update_net_params_callback) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  DCHECK(prefs);
+
+  base::Closure prefs_callback =
+      base::Bind(&NetPrefObserver::ApplySettings, base::Unretained(this));
+  quic_allowed_.Init(prefs::kQuicAllowed, prefs, prefs_callback);
+
+  ApplySettings();
+}
+
+NetPrefObserver::~NetPrefObserver() {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+}
+
+void NetPrefObserver::ApplySettings() {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+
+  IOThread* io_thread = g_browser_process->io_thread();
+  if (!io_thread)
+    return;
+
+  bool quic_allowed_for_profile = true;
+  if (quic_allowed_.IsManaged())
+    quic_allowed_for_profile = *quic_allowed_;
+
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      base::Bind(&NetPrefObserver::ApplySettingsOnIOThread,
+                 base::Unretained(this), io_thread,
+                 base::Unretained(g_browser_process->safe_browsing_service()),
+                 quic_allowed_for_profile));
+}
+
+void NetPrefObserver::ApplySettingsOnIOThread(
+    IOThread* io_thread,
+    safe_browsing::SafeBrowsingService* safe_browsing_service,
+    bool quic_allowed_for_profile) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
+  // Never re-enable QUIC if it was disallowed on startup, e.g. due to command
+  // line flags.
+  bool quic_allowed_on_startup = io_thread->NetworkSessionParams().enable_quic;
+  if (!quic_allowed_on_startup)
+    return;
+
+  net::HttpNetworkSession::ParamsUpdate params_update;
+  params_update.enable_quic_new = quic_allowed_for_profile;
+
+  // Make the profile adhere to its current setting by invoking its callback.
+  update_net_params_callback_.Run(params_update);
+
+  // Globally-owned HttpNetworkSessions should only be updated if QUIC is being
+  // turned off. This "kill switch"-like behavior prevents multiple Profiles
+  // fighting over QUIC enablement for global HttpNetworkSessions.
+  if (!quic_allowed_for_profile) {
+    io_thread->UpdateNetworkSessionParams(params_update);
+
+    safe_browsing_service->UpdateNetParamsOnIOThread(params_update);
+  }
+}
+
+// static
+void NetPrefObserver::RegisterProfilePrefs(
+    user_prefs::PrefRegistrySyncable* registry) {
+  registry->RegisterBooleanPref(prefs::kQuicAllowed, true);
+}