Replace LoggingNetworkChangeObserver in IOSIOThread with class from net/

IPAddressObserver and ConnectionTypeObserver are deprecated in favor of
NetworkChangeObserver.  This CL replaces a class that subclasses them with
an (almost identical) internal class which does not expose them directly.

For more details see the design doc linked in the bug below.

Bug: 754695
Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: Ic65ce6aa4df57893504e9eaf3042fb2deb355115
Reviewed-on: https://chromium-review.googlesource.com/1133325
Commit-Queue: Lily Houghton <lilyhoughton@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Paul Jensen <pauljensen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577181}

ios/components/io_thread/ios_io_thread.h

@@ -38,6 +38,7 @@ class HttpAuthPreferences;
 class HttpServerProperties;
 class HttpTransactionFactory;
 class HttpUserAgentSettings;
+class LoggingNetworkChangeObserver;
 class NetworkDelegate;
 class ProxyConfigService;
 class ProxyResolutionService;
@@ -201,8 +202,7 @@ class IOSIOThread : public web::WebThreadDelegate {
   net::HttpNetworkSession::Params params_;
 
   // Observer that logs network changes to the ChromeNetLog.
-  class LoggingNetworkChangeObserver;
-  std::unique_ptr<LoggingNetworkChangeObserver> network_change_observer_;
+  std::unique_ptr<net::LoggingNetworkChangeObserver> network_change_observer_;
 
   // These member variables are initialized by a task posted to the IO thread,
   // which gets posted by calling certain member functions of IOSIOThread.

ios/components/io_thread/ios_io_thread.mm

@@ -36,6 +36,7 @@
 #include "ios/web/public/user_agent.h"
 #include "ios/web/public/web_client.h"
 #include "ios/web/public/web_thread.h"
+#include "net/base/logging_network_change_observer.h"
 #include "net/cert/cert_verifier.h"
 #include "net/cert/ct_policy_enforcer.h"
 #include "net/cert/ct_verifier.h"
@@ -103,65 +104,6 @@ std::unique_ptr<net::HostResolver> CreateGlobalHostResolver(
   return global_host_resolver;
 }
 
-class IOSIOThread::LoggingNetworkChangeObserver
-    : public net::NetworkChangeNotifier::IPAddressObserver,
-      public net::NetworkChangeNotifier::ConnectionTypeObserver,
-      public net::NetworkChangeNotifier::NetworkChangeObserver {
- public:
-  // |net_log| must remain valid throughout our lifetime.
-  explicit LoggingNetworkChangeObserver(net::NetLog* net_log)
-      : net_log_(net_log) {
-    net::NetworkChangeNotifier::AddIPAddressObserver(this);
-    net::NetworkChangeNotifier::AddConnectionTypeObserver(this);
-    net::NetworkChangeNotifier::AddNetworkChangeObserver(this);
-  }
-
-  ~LoggingNetworkChangeObserver() override {
-    net::NetworkChangeNotifier::RemoveIPAddressObserver(this);
-    net::NetworkChangeNotifier::RemoveConnectionTypeObserver(this);
-    net::NetworkChangeNotifier::RemoveNetworkChangeObserver(this);
-  }
-
-  // NetworkChangeNotifier::IPAddressObserver implementation.
-  void OnIPAddressChanged() override {
-    VLOG(1) << "Observed a change to the network IP addresses";
-
-    net_log_->AddGlobalEntry(
-        net::NetLogEventType::NETWORK_IP_ADDRESSES_CHANGED);
-  }
-
-  // NetworkChangeNotifier::ConnectionTypeObserver implementation.
-  void OnConnectionTypeChanged(
-      net::NetworkChangeNotifier::ConnectionType type) override {
-    std::string type_as_string =
-        net::NetworkChangeNotifier::ConnectionTypeToString(type);
-
-    VLOG(1) << "Observed a change to network connectivity state "
-            << type_as_string;
-
-    net_log_->AddGlobalEntry(
-        net::NetLogEventType::NETWORK_CONNECTIVITY_CHANGED,
-        net::NetLog::StringCallback("new_connection_type", &type_as_string));
-  }
-
-  // NetworkChangeNotifier::NetworkChangeObserver implementation.
-  void OnNetworkChanged(
-      net::NetworkChangeNotifier::ConnectionType type) override {
-    std::string type_as_string =
-        net::NetworkChangeNotifier::ConnectionTypeToString(type);
-
-    VLOG(1) << "Observed a network change to state " << type_as_string;
-
-    net_log_->AddGlobalEntry(
-        net::NetLogEventType::NETWORK_CHANGED,
-        net::NetLog::StringCallback("new_connection_type", &type_as_string));
-  }
-
- private:
-  net::NetLog* net_log_;
-  DISALLOW_COPY_AND_ASSIGN(LoggingNetworkChangeObserver);
-};
-
 class SystemURLRequestContextGetter : public net::URLRequestContextGetter {
  public:
   explicit SystemURLRequestContextGetter(IOSIOThread* io_thread);
@@ -298,7 +240,8 @@ void IOSIOThread::Init() {
   // Add an observer that will emit network change events to the ChromeNetLog.
   // Assuming NetworkChangeNotifier dispatches in FIFO order, we should be
   // logging the network change before other IO thread consumers respond to it.
-  network_change_observer_.reset(new LoggingNetworkChangeObserver(net_log_));
+  network_change_observer_ =
+      std::make_unique<net::LoggingNetworkChangeObserver>(net_log_);
 
   globals_->system_network_delegate = CreateSystemNetworkDelegate();
   globals_->host_resolver = CreateGlobalHostResolver(net_log_);