Pass NetworkMonitorFactory through PeerConnectionFactory.

Previously the instance was set through a static method, which was
really only done because it was difficult to add new
PeerConnectionFactory construction arguments at the time.

Now that we have PeerConnectionFactoryDependencies it's easy to clean
this up.

I'm doing this because I plan to add a NetworkMonitor implementation
for iOS, and don't want to inherit this ugliness.

Bug: webrtc:9883
Change-Id: Id94dc061ab1c7186b81af8547393a6e336ff04c2
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/180241
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Sami Kalliomäki <sakal@webrtc.org>
Commit-Queue: Taylor <deadbeef@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31815}

rtc_base/network.h

@@ -23,8 +23,11 @@
 #include "rtc_base/mdns_responder_interface.h"
 #include "rtc_base/message_handler.h"
 #include "rtc_base/network_monitor.h"
+#include "rtc_base/network_monitor_factory.h"
+#include "rtc_base/synchronization/sequence_checker.h"
 #include "rtc_base/system/rtc_export.h"
 #include "rtc_base/third_party/sigslot/sigslot.h"
+#include "rtc_base/thread_annotations.h"
 
 #if defined(WEBRTC_POSIX)
 struct ifaddrs;
@@ -221,6 +224,7 @@ class RTC_EXPORT BasicNetworkManager : public NetworkManagerBase,
                                        public sigslot::has_slots<> {
  public:
   BasicNetworkManager();
+  explicit BasicNetworkManager(NetworkMonitorFactory* network_monitor_factory);
   ~BasicNetworkManager() override;
 
   void StartUpdating() override;
@@ -234,7 +238,9 @@ class RTC_EXPORT BasicNetworkManager : public NetworkManagerBase,
 
   // Sets the network ignore list, which is empty by default. Any network on the
   // ignore list will be filtered from network enumeration results.
+  // Should be called only before initialization.
   void set_network_ignore_list(const std::vector<std::string>& list) {
+    RTC_DCHECK(thread_ == nullptr);
     network_ignore_list_ = list;
   }
 
@@ -244,41 +250,45 @@ class RTC_EXPORT BasicNetworkManager : public NetworkManagerBase,
   void ConvertIfAddrs(ifaddrs* interfaces,
                       IfAddrsConverter* converter,
                       bool include_ignored,
-                      NetworkList* networks) const;
+                      NetworkList* networks) const RTC_RUN_ON(thread_);
 #endif  // defined(WEBRTC_POSIX)
 
   // Creates a network object for each network available on the machine.
-  bool CreateNetworks(bool include_ignored, NetworkList* networks) const;
+  bool CreateNetworks(bool include_ignored, NetworkList* networks) const
+      RTC_RUN_ON(thread_);
 
   // Determines if a network should be ignored. This should only be determined
   // based on the network's property instead of any individual IP.
-  bool IsIgnoredNetwork(const Network& network) const;
+  bool IsIgnoredNetwork(const Network& network) const RTC_RUN_ON(thread_);
 
   // This function connects a UDP socket to a public address and returns the
   // local address associated it. Since it binds to the "any" address
   // internally, it returns the default local address on a multi-homed endpoint.
-  IPAddress QueryDefaultLocalAddress(int family) const;
+  IPAddress QueryDefaultLocalAddress(int family) const RTC_RUN_ON(thread_);
 
  private:
   friend class NetworkTest;
 
   // Creates a network monitor and listens for network updates.
-  void StartNetworkMonitor();
+  void StartNetworkMonitor() RTC_RUN_ON(thread_);
   // Stops and removes the network monitor.
-  void StopNetworkMonitor();
+  void StopNetworkMonitor() RTC_RUN_ON(thread_);
   // Called when it receives updates from the network monitor.
   void OnNetworksChanged();
 
   // Updates the networks and reschedules the next update.
-  void UpdateNetworksContinually();
+  void UpdateNetworksContinually() RTC_RUN_ON(thread_);
   // Only updates the networks; does not reschedule the next update.
-  void UpdateNetworksOnce();
+  void UpdateNetworksOnce() RTC_RUN_ON(thread_);
 
-  Thread* thread_;
-  bool sent_first_update_;
-  int start_count_;
+  Thread* thread_ = nullptr;
+  bool sent_first_update_ = true;
+  int start_count_ = 0;
   std::vector<std::string> network_ignore_list_;
-  std::unique_ptr<NetworkMonitorInterface> network_monitor_;
+  NetworkMonitorFactory* network_monitor_factory_ RTC_GUARDED_BY(thread_) =
+      nullptr;
+  std::unique_ptr<NetworkMonitorInterface> network_monitor_
+      RTC_GUARDED_BY(thread_);
 };
 
 // Represents a Unix-type network interface, with a name and single address.