Provide Shill IP Address to myIpAddress()

On Chrome OS we need to get the IP Address to use for myIpAddress() from Shill since gethostname() returns localhost.

BUG=175652
TBR=sky@chromium.org

Review URL: https://codereview.chromium.org/238433003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@277679 0039d316-1c4b-4281-b951-d872f2087c98

8 files changed, 487 insertions, 1 deletions

diff --git a/chromeos/chromeos.gyp b/chromeos/chromeos.gyp
index 686b7ae..58aea83 100644
--- a/chromeos/chromeos.gyp
+++ b/chromeos/chromeos.gyp
@@ -276,6 +276,8 @@
         'network/device_state.h',
         'network/geolocation_handler.cc',
         'network/geolocation_handler.h',
+        'network/host_resolver_impl_chromeos.cc',
+       	'network/host_resolver_impl_chromeos.h',
         'network/managed_network_configuration_handler.cc',
         'network/managed_network_configuration_handler.h',
         'network/managed_network_configuration_handler_impl.cc',
@@ -520,6 +522,7 @@
         'login/login_state_unittest.cc',
         'network/client_cert_resolver_unittest.cc',
         'network/geolocation_handler_unittest.cc',
+	'network/host_resolver_impl_chromeos_unittest.cc',
         'network/managed_network_configuration_handler_unittest.cc',
         'network/network_cert_migrator_unittest.cc',
         'network/network_change_notifier_chromeos_unittest.cc',
diff --git a/chromeos/network/device_state.h b/chromeos/network/device_state.h
index 5f4486d..3e8195b 100644
--- a/chromeos/network/device_state.h
+++ b/chromeos/network/device_state.h
@@ -49,10 +49,12 @@ class CHROMEOS_EXPORT DeviceState : public ManagedState {
   const std::string& mdn() const { return mdn_; }
   const CellularScanResults& scan_results() const { return scan_results_; }
 
+  // |ip_configs_| is kept up to date by NetworkStateHandler.
+  const base::DictionaryValue& ip_configs() const { return ip_configs_; }
+
   // Do not use this. It exists temporarily for internet_options_handler.cc
   // which is being deprecated.
   const base::DictionaryValue& properties() const { return properties_; }
-  const base::DictionaryValue& ip_configs() const { return ip_configs_; }
 
   // Ethernet specific accessors
   bool eap_authentication_completed() const {
diff --git a/chromeos/network/host_resolver_impl_chromeos.cc b/chromeos/network/host_resolver_impl_chromeos.cc
new file mode 100644
index 0000000..ad946e5
--- /dev/null
+++ b/chromeos/network/host_resolver_impl_chromeos.cc
@@ -0,0 +1,214 @@
+// Copyright 2014 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 "chromeos/network/host_resolver_impl_chromeos.h"
+
+#include "base/message_loop/message_loop_proxy.h"
+#include "base/values.h"
+#include "chromeos/network/device_state.h"
+#include "chromeos/network/network_handler.h"
+#include "chromeos/network/network_state.h"
+#include "chromeos/network/network_state_handler.h"
+#include "chromeos/network/network_state_handler_observer.h"
+#include "net/base/address_list.h"
+#include "net/base/net_errors.h"
+#include "net/base/net_util.h"
+#include "third_party/cros_system_api/dbus/service_constants.h"
+
+namespace chromeos {
+
+// HostResolverImplChromeOS::NetworkStateHandlerObserver
+//
+// An instance of this class is created on the NetworkHandler (UI) thread and
+// manages its own lifetime, destroying itself when NetworkStateHandlerObserver
+// ::IsShuttingDown() gets called.
+
+class HostResolverImplChromeOS::NetworkObserver
+    : public chromeos::NetworkStateHandlerObserver {
+ public:
+  static void Create(
+      const base::WeakPtr<HostResolverImplChromeOS>& resolver,
+      scoped_refptr<base::MessageLoopProxy> resolver_message_loop,
+      NetworkStateHandler* network_state_handler) {
+    new NetworkObserver(resolver, resolver_message_loop, network_state_handler);
+  }
+
+  NetworkObserver(const base::WeakPtr<HostResolverImplChromeOS>& resolver,
+                  scoped_refptr<base::MessageLoopProxy> resolver_message_loop,
+                  NetworkStateHandler* network_state_handler)
+      : resolver_(resolver),
+        resolver_message_loop_(resolver_message_loop),
+        network_state_handler_(network_state_handler),
+        weak_ptr_factory_resolver_thread_(this) {
+    network_state_handler_->AddObserver(this, FROM_HERE);
+    DefaultNetworkChanged(network_state_handler_->DefaultNetwork());
+  }
+
+ private:
+  virtual ~NetworkObserver() {
+    network_state_handler_->RemoveObserver(this, FROM_HERE);
+  }
+
+  // NetworkStateHandlerObserver
+  virtual void DefaultNetworkChanged(const NetworkState* network) OVERRIDE {
+    if (!network) {
+      DVLOG(2) << "DefaultNetworkChanged: No Network.";
+      CallResolverSetIpAddress("", "");
+      return;
+    }
+    std::string ipv4_address, ipv6_address;
+    const DeviceState* device_state =
+        network_state_handler_->GetDeviceState(network->device_path());
+    if (!device_state) {
+      LOG(ERROR) << "DefaultNetworkChanged: Network missing device: "
+                 << network->path();
+      CallResolverSetIpAddress("", "");
+      return;
+    }
+    for (base::DictionaryValue::Iterator iter(device_state->ip_configs());
+         !iter.IsAtEnd(); iter.Advance()) {
+      const base::DictionaryValue* ip_config;
+      if (!iter.value().GetAsDictionary(&ip_config)) {
+        LOG(ERROR) << "Badly formatted IPConfigs: " << network->path();
+        continue;
+      }
+      std::string method, address;
+      if (ip_config->GetString(shill::kMethodProperty, &method) &&
+          ip_config->GetString(shill::kAddressProperty, &address)) {
+        if (method == shill::kTypeIPv4 || method == shill::kTypeDHCP)
+          ipv4_address = address;
+        else if (method == shill::kTypeIPv6 || method == shill::kTypeDHCP6)
+          ipv6_address = address;
+      } else {
+        LOG(ERROR) << "DefaultNetworkChanged: IPConfigs missing properties: "
+                   << network->path();
+      }
+    }
+    DVLOG(2) << "DefaultNetworkChanged: " << network->name()
+             << " IPv4: " << ipv4_address << " IPv6: " << ipv6_address;
+    CallResolverSetIpAddress(ipv4_address, ipv6_address);
+  }
+
+  virtual void IsShuttingDown() OVERRIDE {
+    delete this;
+  }
+
+  void CallResolverSetIpAddress(const std::string& ipv4_address,
+                                const std::string& ipv6_address) {
+    resolver_message_loop_->PostTask(
+        FROM_HERE,
+        base::Bind(&NetworkObserver::SetIpAddressOnResolverThread,
+                   weak_ptr_factory_resolver_thread_.GetWeakPtr(),
+                   ipv4_address, ipv6_address));
+  }
+
+  void SetIpAddressOnResolverThread(const std::string& ipv4_address,
+                                    const std::string& ipv6_address) {
+    if (resolver_)
+      resolver_->SetIPAddresses(ipv4_address, ipv6_address);
+  }
+
+  base::WeakPtr<HostResolverImplChromeOS> resolver_;
+  scoped_refptr<base::MessageLoopProxy> resolver_message_loop_;
+  NetworkStateHandler* network_state_handler_;
+  base::WeakPtrFactory<NetworkObserver> weak_ptr_factory_resolver_thread_;
+
+  DISALLOW_COPY_AND_ASSIGN(NetworkObserver);
+};
+
+// HostResolverImplChromeOS
+
+HostResolverImplChromeOS::HostResolverImplChromeOS(
+    scoped_refptr<base::MessageLoopProxy> network_handler_message_loop,
+    NetworkStateHandler* network_state_handler,
+    const Options& options,
+    net::NetLog* net_log)
+    : HostResolverImpl(options, net_log),
+      network_handler_message_loop_(network_handler_message_loop),
+      weak_ptr_factory_(this) {
+  network_handler_message_loop->PostTask(
+      FROM_HERE,
+      base::Bind(&NetworkObserver::Create,
+                 weak_ptr_factory_.GetWeakPtr(),
+                 base::MessageLoopProxy::current(),
+                 network_state_handler));
+}
+
+HostResolverImplChromeOS::~HostResolverImplChromeOS() {
+}
+
+int HostResolverImplChromeOS::Resolve(const RequestInfo& info,
+                                      net::RequestPriority priority,
+                                      net::AddressList* addresses,
+                                      const net::CompletionCallback& callback,
+                                      RequestHandle* out_req,
+                                      const net::BoundNetLog& source_net_log) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  if (ResolveLocalIPAddress(info, addresses))
+    return net::OK;
+  return net::HostResolverImpl::Resolve(
+      info, priority, addresses, callback, out_req, source_net_log);
+}
+
+void HostResolverImplChromeOS::SetIPAddresses(const std::string& ipv4_address,
+                                              const std::string& ipv6_address) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  ipv4_address_ = ipv4_address;
+  ipv6_address_ = ipv6_address;
+}
+
+bool HostResolverImplChromeOS::ResolveLocalIPAddress(
+    const RequestInfo& info,
+    net::AddressList* addresses) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  if (info.hostname() != net::GetHostName() || ipv4_address_.empty())
+    return false;
+
+  // Use IPConfig data for localhost address lookup.
+  addresses->clear();
+
+  if (info.address_family() != net::ADDRESS_FAMILY_IPV4 &&
+      !ipv6_address_.empty()) {
+    net::IPAddressNumber ipv6;
+    if (net::ParseIPLiteralToNumber(ipv6_address_, &ipv6))
+      addresses->push_back(net::IPEndPoint(ipv6, 0));
+  }
+
+  net::IPAddressNumber ipv4;
+  if (net::ParseIPLiteralToNumber(ipv4_address_, &ipv4))
+    addresses->push_back(net::IPEndPoint(ipv4, 0));
+
+  DVLOG(2) << "ResolveLocalIPAddress("
+           << static_cast<int>(info.address_family()) << "): "
+           << addresses->size()
+           << " IPv4: " << ipv4_address_ << " IPv6: " << ipv6_address_;
+  addresses->SetDefaultCanonicalName();
+  return true;
+}
+
+// static
+scoped_ptr<net::HostResolver> HostResolverImplChromeOS::CreateSystemResolver(
+    const Options& options,
+    net::NetLog* net_log) {
+  return scoped_ptr<net::HostResolver>(new HostResolverImplChromeOS(
+      NetworkHandler::Get()->message_loop(),
+      NetworkHandler::Get()->network_state_handler(),
+      options,
+      net_log));
+}
+
+// static
+scoped_ptr<net::HostResolver>
+HostResolverImplChromeOS::CreateHostResolverForTest(
+    scoped_refptr<base::MessageLoopProxy> network_handler_message_loop,
+    NetworkStateHandler* network_state_handler) {
+  Options options;
+  return scoped_ptr<net::HostResolver>(new HostResolverImplChromeOS(
+      network_handler_message_loop,
+      network_state_handler,
+      options,
+      NULL));
+}
+
+}  // namespace chromeos
diff --git a/chromeos/network/host_resolver_impl_chromeos.h b/chromeos/network/host_resolver_impl_chromeos.h
new file mode 100644
index 0000000..94f7712
--- /dev/null
+++ b/chromeos/network/host_resolver_impl_chromeos.h
@@ -0,0 +1,80 @@
+// Copyright 2014 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 CHROMEOS_NETWORK_HOST_RESOLVER_IMPL_CHROMEOS_H_
+#define CHROMEOS_NETWORK_HOST_RESOLVER_IMPL_CHROMEOS_H_
+
+#include "base/memory/ref_counted.h"
+#include "base/threading/thread_checker.h"
+#include "chromeos/chromeos_export.h"
+#include "net/dns/host_resolver_impl.h"
+
+namespace base {
+class MessageLoopProxy;
+}
+
+namespace chromeos {
+class NetworkStateHandler;
+}
+
+namespace chromeos {
+
+// HostResolverImplChromeOS overrides HostResolverImpl::Resolve in order to
+// provide the correct IP addresses for localhost using the chromeos
+// NetworkHandler interface. ('hostname' only returns 'localhost' on cros).
+
+class CHROMEOS_EXPORT HostResolverImplChromeOS : public net::HostResolverImpl {
+ public:
+  // ChromeOS specific implementation of HostResolver::CreateSystemResolver.
+  // Assumes NetworkHandler has been initialized.
+  // This is expected to be constructed on the same thread that Resolve() is
+  // called from, i.e. the IO thread, which is presumed to differ from the
+  // thread that NetworkStateHandler is called on, i.e. the UI thread.
+  static scoped_ptr<net::HostResolver> CreateSystemResolver(
+      const Options& options,
+      net::NetLog* net_log);
+
+  // Creates a host resolver instance for testing.
+  static scoped_ptr<net::HostResolver> CreateHostResolverForTest(
+      scoped_refptr<base::MessageLoopProxy> network_handler_message_loop,
+      NetworkStateHandler* network_state_handler);
+
+  virtual ~HostResolverImplChromeOS();
+
+  // HostResolverImpl
+  virtual int Resolve(const RequestInfo& info,
+                      net::RequestPriority priority,
+                      net::AddressList* addresses,
+                      const net::CompletionCallback& callback,
+                      RequestHandle* out_req,
+                      const net::BoundNetLog& source_net_log) OVERRIDE;
+
+ private:
+  friend class net::HostResolver;
+  class NetworkObserver;
+
+  HostResolverImplChromeOS(
+      scoped_refptr<base::MessageLoopProxy> network_handler_message_loop,
+      NetworkStateHandler* network_state_handler,
+      const Options& options,
+      net::NetLog* net_log);
+
+  void SetIPAddresses(const std::string& ipv4_address,
+                      const std::string& ipv6_address);
+
+  bool ResolveLocalIPAddress(const RequestInfo& info,
+                             net::AddressList* addresses);
+
+  std::string ipv4_address_;
+  std::string ipv6_address_;
+  base::ThreadChecker thread_checker_;
+  scoped_refptr<base::MessageLoopProxy> network_handler_message_loop_;
+  base::WeakPtrFactory<HostResolverImplChromeOS> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(HostResolverImplChromeOS);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROMEOS_NETWORK_HOST_RESOLVER_IMPL_CHROMEOS_H_
diff --git a/chromeos/network/host_resolver_impl_chromeos_unittest.cc b/chromeos/network/host_resolver_impl_chromeos_unittest.cc
new file mode 100644
index 0000000..535eec9
--- /dev/null
+++ b/chromeos/network/host_resolver_impl_chromeos_unittest.cc
@@ -0,0 +1,171 @@
+// Copyright 2014 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 "chromeos/network/host_resolver_impl_chromeos.h"
+
+#include "base/memory/scoped_ptr.h"
+#include "base/message_loop/message_loop.h"
+#include "base/run_loop.h"
+#include "base/strings/stringprintf.h"
+#include "chromeos/dbus/dbus_thread_manager.h"
+#include "chromeos/dbus/shill_device_client.h"
+#include "chromeos/dbus/shill_ipconfig_client.h"
+#include "chromeos/dbus/shill_service_client.h"
+#include "chromeos/network/device_state.h"
+#include "chromeos/network/network_state.h"
+#include "chromeos/network/network_state_handler.h"
+#include "dbus/object_path.h"
+#include "net/base/net_errors.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/cros_system_api/dbus/service_constants.h"
+
+namespace {
+
+const char kTestIPv4Address[] = "1.2.3.4";
+const char kTestIPv6Address[] = "1:2:3:4:5:6:7:8";
+
+void DoNothingWithCallStatus(chromeos::DBusMethodCallStatus call_status) {}
+void ErrorCallbackFunction(const std::string& error_name,
+                           const std::string& error_message) {
+  LOG(ERROR) << "Shill Error: " << error_name << " : " << error_message;
+}
+void ResolveCompletionCallback(int result) {}
+
+}  // namespace
+
+class HostResolverImplChromeOSTest : public testing::Test {
+ public:
+  HostResolverImplChromeOSTest() {}
+
+  virtual ~HostResolverImplChromeOSTest() {}
+
+  virtual void SetUp() OVERRIDE {
+    chromeos::DBusThreadManager::InitializeWithStub();
+
+    network_state_handler_.reset(
+        chromeos::NetworkStateHandler::InitializeForTest());
+    base::RunLoop().RunUntilIdle();
+
+    const chromeos::NetworkState* default_network =
+        network_state_handler_->DefaultNetwork();
+    ASSERT_TRUE(default_network);
+    const chromeos::DeviceState* default_device =
+        network_state_handler_->GetDeviceState(default_network->device_path());
+    ASSERT_TRUE(default_device);
+    SetDefaultIPConfigs(default_device->path());
+
+    // Create the host resolver from the IO message loop.
+    io_message_loop_.PostTask(
+        FROM_HERE,
+        base::Bind(&HostResolverImplChromeOSTest::InitializeHostResolver,
+                   base::Unretained(this)));
+    io_message_loop_.RunUntilIdle();
+
+    // Run the main message loop to create the network observer and initialize
+    // the ip address values.
+    base::RunLoop().RunUntilIdle();
+  }
+
+  virtual void TearDown() OVERRIDE {
+    network_state_handler_.reset();
+    chromeos::DBusThreadManager::Shutdown();
+  }
+
+ protected:
+  // Run from main (UI) message loop, calls Resolve on IO message loop.
+  int CallResolve(net::HostResolver::RequestInfo& info) {
+    io_message_loop_.PostTask(
+        FROM_HERE,
+        base::Bind(&HostResolverImplChromeOSTest::Resolve,
+                   base::Unretained(this),
+                   info));
+    io_message_loop_.RunUntilIdle();
+    return result_;
+  }
+
+  net::AddressList addresses_;
+  int result_;
+
+ private:
+  // Run from IO message loop.
+  void InitializeHostResolver() {
+    net::HostResolver::Options options;
+    host_resolver_ =
+        chromeos::HostResolverImplChromeOS::CreateHostResolverForTest(
+            base::MessageLoopProxy::current(),
+            network_state_handler_.get());
+  }
+
+  // Run from IO message loop.
+  void Resolve(net::HostResolver::RequestInfo info) {
+    result_ = host_resolver_->Resolve(
+        info,
+        net::DEFAULT_PRIORITY,
+        &addresses_,
+        base::Bind(&ResolveCompletionCallback),
+        NULL,
+        net_log_);
+  }
+
+  void SetDefaultIPConfigs(const std::string& default_device_path) {
+    const std::string kTestIPv4ConfigPath("test_ip_v4_config_path");
+    const std::string kTestIPv6ConfigPath("test_ip_v6_config_path");
+
+    SetIPConfig(kTestIPv4ConfigPath, shill::kTypeIPv4, kTestIPv4Address);
+    SetIPConfig(kTestIPv6ConfigPath, shill::kTypeIPv6, kTestIPv6Address);
+    base::RunLoop().RunUntilIdle();
+
+    base::ListValue ip_configs;
+    ip_configs.AppendString(kTestIPv4ConfigPath);
+    ip_configs.AppendString(kTestIPv6ConfigPath);
+
+    chromeos::DBusThreadManager::Get()->GetShillDeviceClient()->SetProperty(
+        dbus::ObjectPath(default_device_path),
+        shill::kIPConfigsProperty,
+        ip_configs,
+        base::Bind(&base::DoNothing),
+        base::Bind(&ErrorCallbackFunction));
+    base::RunLoop().RunUntilIdle();
+  }
+
+  void SetIPConfig(const std::string& path,
+                   const std::string& method,
+                   const std::string& address) {
+    chromeos::DBusThreadManager::Get()->GetShillIPConfigClient()->SetProperty(
+        dbus::ObjectPath(path),
+        shill::kAddressProperty,
+        base::StringValue(address),
+        base::Bind(&DoNothingWithCallStatus));
+    chromeos::DBusThreadManager::Get()->GetShillIPConfigClient()->SetProperty(
+        dbus::ObjectPath(path),
+        shill::kMethodProperty,
+        base::StringValue(method),
+        base::Bind(&DoNothingWithCallStatus));
+  }
+
+  scoped_ptr<chromeos::NetworkStateHandler> network_state_handler_;
+  scoped_ptr<net::HostResolver> host_resolver_;
+  base::MessageLoop io_message_loop_;
+  net::BoundNetLog net_log_;
+
+  DISALLOW_COPY_AND_ASSIGN(HostResolverImplChromeOSTest);
+};
+
+TEST_F(HostResolverImplChromeOSTest, Resolve) {
+  net::HostResolver::RequestInfo info(
+      net::HostPortPair(net::GetHostName(), 80));
+  info.set_address_family(net::ADDRESS_FAMILY_IPV4);
+  EXPECT_EQ(net::OK, CallResolve(info));
+  ASSERT_EQ(1u, addresses_.size());
+  std::string expected = base::StringPrintf("%s:%d", kTestIPv4Address, 0);
+  EXPECT_EQ(expected, addresses_[0].ToString());
+
+  info.set_address_family(net::ADDRESS_FAMILY_IPV6);
+  EXPECT_EQ(net::OK, CallResolve(info));
+  ASSERT_EQ(2u, addresses_.size());
+  expected = base::StringPrintf("[%s]:%d", kTestIPv6Address, 0);
+  EXPECT_EQ(expected, addresses_[0].ToString());
+  expected = base::StringPrintf("%s:%d", kTestIPv4Address, 0);
+  EXPECT_EQ(expected, addresses_[1].ToString());
+}
diff --git a/chromeos/network/network_state_handler.cc b/chromeos/network/network_state_handler.cc
index aa91883..e4e5f6e 100644
--- a/chromeos/network/network_state_handler.cc
+++ b/chromeos/network/network_state_handler.cc
@@ -60,6 +60,7 @@ NetworkStateHandler::NetworkStateHandler() {
 }
 
 NetworkStateHandler::~NetworkStateHandler() {
+  FOR_EACH_OBSERVER(NetworkStateHandlerObserver, observers_, IsShuttingDown());
   STLDeleteContainerPointers(network_list_.begin(), network_list_.end());
   STLDeleteContainerPointers(device_list_.begin(), device_list_.end());
 }
@@ -658,11 +659,19 @@ void NetworkStateHandler::UpdateIPConfigProperties(
     if (!network)
       return;
     network->IPConfigPropertiesChanged(properties);
+    if (network->path() == default_network_path_)
+      NotifyDefaultNetworkChanged(network);
   } else if (type == ManagedState::MANAGED_TYPE_DEVICE) {
     DeviceState* device = GetModifiableDeviceState(path);
     if (!device)
       return;
     device->IPConfigPropertiesChanged(ip_config_path, properties);
+    if (!default_network_path_.empty()) {
+      const NetworkState* default_network =
+          GetNetworkState(default_network_path_);
+      if (default_network && default_network->device_path() == path)
+        NotifyDefaultNetworkChanged(default_network);
+    }
   }
 }
 
diff --git a/chromeos/network/network_state_handler_observer.cc b/chromeos/network/network_state_handler_observer.cc
index b0cab57..0914e6b 100644
--- a/chromeos/network/network_state_handler_observer.cc
+++ b/chromeos/network/network_state_handler_observer.cc
@@ -30,4 +30,7 @@ void NetworkStateHandlerObserver::NetworkPropertiesUpdated(
     const NetworkState* network) {
 }
 
+void NetworkStateHandlerObserver::IsShuttingDown() {
+}
+
 }  // namespace chromeos
diff --git a/chromeos/network/network_state_handler_observer.h b/chromeos/network/network_state_handler_observer.h
index ef33c6f..63910c4 100644
--- a/chromeos/network/network_state_handler_observer.h
+++ b/chromeos/network/network_state_handler_observer.h
@@ -44,6 +44,10 @@ class CHROMEOS_EXPORT NetworkStateHandlerObserver {
   // wifi strength.
   virtual void NetworkPropertiesUpdated(const NetworkState* network);
 
+  // Called just before NetworkStateHandler is destroyed so that observers
+  // can safely stop observing.
+  virtual void IsShuttingDown();
+
  private:
   DISALLOW_COPY_AND_ASSIGN(NetworkStateHandlerObserver);
 };