[CrOS Tether] Add disconnect handling to NetworkConnectionHandler::TetherDelegate.

chromeos/network/network_connection_handler.h

Index: chromeos/network/network_connection_handler.h
diff --git a/chromeos/network/network_connection_handler.h b/chromeos/network/network_connection_handler.h
index 875ee00c1c53182fef8219729c27f00dec752f5e..625964a85272dfe89364da697f68da1a358ffe2d 100644
--- a/chromeos/network/network_connection_handler.h
+++ b/chromeos/network/network_connection_handler.h
@@ -74,7 +74,7 @@ class CHROMEOS_EXPORT NetworkConnectionHandler {
   // connecting.
   static const char kErrorConnectFailed[];
 
-  // An unexpected DBus or Shill error occurred while disconnecting.
+  // An unexpected DBus, Shill, or Tether error occurred while disconnecting.
   static const char kErrorDisconnectFailed[];
 
   // A new network connect request canceled this one.
@@ -95,8 +95,9 @@ class CHROMEOS_EXPORT NetworkConnectionHandler {
   // Network was enabled/disabled when it was not available.
   static const char kErrorEnabledOrDisabledWhenNotAvailable[];
 
-  // Connection to Tether network attempted when no tether delegate present.
-  static const char kErrorTetherConnectionAttemptWithNoDelegate[];
+  // Connection or disconnection to Tether network attempted when no tether
+  // delegate present.
+  static const char kErrorTetherAttemptWithNoDelegate[];
 
   class CHROMEOS_EXPORT TetherDelegate {
    public:
@@ -108,6 +109,14 @@ class CHROMEOS_EXPORT NetworkConnectionHandler {
         const base::Closure& success_callback,
         const network_handler::StringResultCallback& error_callback) = 0;
 
+    // Disconnects from the Tether network with GUID |tether_network_guid|. On
+    // success, invokes |success_callback|, and on failure, invokes
+    // |error_callback|, passing the relevant error code declared above.
+    virtual void DisconnectFromNetwork(
+        const std::string& tether_network_guid,
+        const base::Closure& success_callback,
+        const network_handler::StringResultCallback& error_callback) = 0;
+
    protected:
     virtual ~TetherDelegate() {}
   };
@@ -179,6 +188,12 @@ class CHROMEOS_EXPORT NetworkConnectionHandler {
       const base::Closure& success_callback,
       const network_handler::ErrorCallback& error_callback);
 
+  // Initiates a disconnection from a Tether network.
+  void InitiateTetherNetworkDisconnection(
+      const std::string& tether_network_guid,
+      const base::Closure& success_callback,
+      const network_handler::ErrorCallback& error_callback);
+
   base::ObserverList<NetworkConnectionObserver, true> observers_;
 
   // Delegate used to start a connection to a tether network.