Add ResetModem method and call it once non_cellular activation is done.

chromeos/dbus/shill_device_client.h

Index: chromeos/dbus/shill_device_client.h
diff --git a/chromeos/dbus/shill_device_client.h b/chromeos/dbus/shill_device_client.h
index 5f7b64de67adee7f545c9c3330498199144f1402..e7490f53310cd578ab2027d72593121f8acf8c1e 100644
--- a/chromeos/dbus/shill_device_client.h
+++ b/chromeos/dbus/shill_device_client.h
@@ -158,6 +158,12 @@ class CHROMEOS_EXPORT ShillDeviceClient {
                           const base::Closure& callback,
                           const ErrorCallback& error_callback) = 0;
 
+  // Calls the Reset method.
+  // |callback| is called after the method call finishes.
+  virtual void Reset(const dbus::ObjectPath& device_path,
+                          const base::Closure& callback,
+                          const ErrorCallback& error_callback) = 0;
+
   // Returns an interface for testing (stub only), or returns NULL.
   virtual TestInterface* GetTestInterface() = 0;