Add API to get current time mode from NetworkEmulationManager

Bug: None
Change-Id: I1aeca7484bab2b9bc28684b055b8f6bb86135327
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/203888
Reviewed-by: Andrey Logvin <landrey@webrtc.org>
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33074}

api/test/network_emulation_manager.h

@@ -167,6 +167,8 @@ class NetworkEmulationManager {
   virtual ~NetworkEmulationManager() = default;
 
   virtual TimeController* time_controller() = 0;
+  // Returns a mode in which underlying time controller operates.
+  virtual TimeMode time_mode() const = 0;
 
   // Creates an emulated network node, which represents single network in
   // the emulated network layer. Uses default implementation on network behavior

test/network/network_emulation_manager.cc

@@ -46,7 +46,8 @@ std::unique_ptr<TimeController> CreateTimeController(TimeMode mode) {
 }  // namespace
 
 NetworkEmulationManagerImpl::NetworkEmulationManagerImpl(TimeMode mode)
-    : time_controller_(CreateTimeController(mode)),
+    : time_mode_(mode),
+      time_controller_(CreateTimeController(mode)),
       clock_(time_controller_->GetClock()),
       next_node_id_(1),
       next_ip4_address_(kMinIPv4Address),

test/network/network_emulation_manager.h

@@ -82,6 +82,8 @@ class NetworkEmulationManagerImpl : public NetworkEmulationManager {
 
   TimeController* time_controller() override { return time_controller_.get(); }
 
+  TimeMode time_mode() const override { return time_mode_; }
+
   Timestamp Now() const;
 
   EmulatedTURNServerInterface* CreateTURNServer(
@@ -92,6 +94,8 @@ class NetworkEmulationManagerImpl : public NetworkEmulationManager {
       std::pair<std::unique_ptr<CrossTrafficGenerator>, RepeatingTaskHandle>;
 
   absl::optional<rtc::IPAddress> GetNextIPv4Address();
+
+  const TimeMode time_mode_;
   const std::unique_ptr<TimeController> time_controller_;
   Clock* const clock_;
   int next_node_id_;