[CrOS Tether] Create KeepAliveScheduler, a class which schedules keep-alive tickles to be sent to a…

chromeos/components/tether/keep_alive_operation.cc

Index: chromeos/components/tether/keep_alive_operation.cc
diff --git a/chromeos/components/tether/keep_alive_operation.cc b/chromeos/components/tether/keep_alive_operation.cc
index d1cf0db97be04614b87f4f73c028252f1231daaa..dc9d54acbab17bcddeb39cb8650590ecfab240c6 100644
--- a/chromeos/components/tether/keep_alive_operation.cc
+++ b/chromeos/components/tether/keep_alive_operation.cc
@@ -48,12 +48,27 @@ KeepAliveOperation::KeepAliveOperation(
 
 KeepAliveOperation::~KeepAliveOperation() {}
 
+void KeepAliveOperation::AddObserver(Observer* observer) {
+  observer_list_.AddObserver(observer);
+}
+
+void KeepAliveOperation::RemoveObserver(Observer* observer) {
+  observer_list_.RemoveObserver(observer);
+}
+
 void KeepAliveOperation::OnDeviceAuthenticated(
     const cryptauth::RemoteDevice& remote_device) {
   DCHECK(remote_devices().size() == 1u && remote_devices()[0] == remote_device);
 
   SendMessageToDevice(remote_device,
                       base::MakeUnique<MessageWrapper>(KeepAliveTickle()));
+  UnregisterDevice(remote_device);
+}
+
+void KeepAliveOperation::OnOperationFinished() {
+  for (auto& observer : observer_list_) {
+    observer.OnOperationFinished();
+  }
 }
 
 MessageType KeepAliveOperation::GetMessageTypeForConnection() {