[CrOS Tether] Add the notion of a tether DeviceState.

chromeos/network/network_state_handler.h

Index: chromeos/network/network_state_handler.h
diff --git a/chromeos/network/network_state_handler.h b/chromeos/network/network_state_handler.h
index 3265b00141c167c6fb162db3ff6a8bcd7cd1ba88..b35887bd5aa6f0629d9fa06fe540d20476548414 100644
--- a/chromeos/network/network_state_handler.h
+++ b/chromeos/network/network_state_handler.h
@@ -112,6 +112,17 @@ class CHROMEOS_EXPORT NetworkStateHandler
       bool enabled,
       const network_handler::ErrorCallback& error_callback);
 
+  // Sets the tether technology state. Because Tether networks do not represent
+  // real Shill networks, this value must be set by the tether component rather
+  // than being generated by Shill. See TetherDeviceStateManager for more
+  // details.
+  void SetTetherTechnologyState(TechnologyState technology_state);
+
+  // Sets the scanning state of the tether technology. Since tether network
+  // scans are not actually performed as part of Shill, this value must be set
+  // by the tether component.
+  void SetTetherScanState(bool is_scanning);
+
   // Asynchronously sets the list of prohibited technologies. The accepted
   // values are the shill network technology identifiers. See also
   // chromeos::onc::Validator::ValidateGlobalNetworkConfiguration().
@@ -250,7 +261,9 @@ class CHROMEOS_EXPORT NetworkStateHandler
                            DeviceStateList* list) const;
 
   // Requests a network scan. This may trigger updates to the network
-  // list, which will trigger the appropriate observer calls.
+  // list, which will trigger the appropriate observer calls. Note that this
+  // function does not request a tether scan.
+  // TODO(khorimoto): Add ability to request a tether scan as well.
   void RequestScan() const;
 
   // Requests an update for an existing NetworkState, e.g. after configuring
@@ -259,7 +272,7 @@ class CHROMEOS_EXPORT NetworkStateHandler
   // acknowledged it (e.g. in the callback of a SetProperties).
   // When the properties are received, NetworkPropertiesUpdated will be
   // signaled for each member of |observers_|, regardless of whether any
-  // properties actually changed.
+  // properties actually changed. Note that this is a no-op for Tether networks.
   void RequestUpdateForNetwork(const std::string& service_path);
 
   // Informs NetworkStateHandler to notify observers that the properties for
@@ -452,6 +465,11 @@ class CHROMEOS_EXPORT NetworkStateHandler
       const std::string& guid,
       const std::string& connection_state);
 
+  // Ensures that the Tether DeviceState is present in |device_list_| if
+  // |tether_technology_state_| is not TECHNOLOGY_UNAVAILABLE and ensures that
+  // it is not present in |device_list_| if it is TECHNOLOGY_UNAVAILABLE.
+  void EnsureTetherDeviceState();
+
   // Shill property handler instance, owned by this class.
   std::unique_ptr<internal::ShillPropertyHandler> shill_property_handler_;
 
@@ -482,6 +500,11 @@ class CHROMEOS_EXPORT NetworkStateHandler
   // NetworkState that is not saved in a profile.
   SpecifierGuidMap specifier_guid_map_;
 
+  // The state corresponding to the tether device type. This value is managed by
+  // the tether component.
+  TechnologyState tether_technology_state_ =
+      TechnologyState::TECHNOLOGY_UNAVAILABLE;
+
   // Ensure that Shutdown() gets called exactly once.
   bool did_shutdown_ = false;