Add SendSignalWithNoArgumentsToSystemBus() to dbus.h

chromeos/dbus/dbus.cc

Index: chromeos/dbus/dbus.cc
diff --git a/chromeos/dbus/dbus.cc b/chromeos/dbus/dbus.cc
index 534883b9a6afb31ddd2eda049e6a76d4767e4654..cfac2ef43a2da9be64c2cfe8e1a4bb2de6b6363e 100644
--- a/chromeos/dbus/dbus.cc
+++ b/chromeos/dbus/dbus.cc
@@ -232,7 +232,29 @@ bool RegisterExclusiveService(const BusConnection& connection,
   return true;
 }
 
-
+void SendSignalWithNoArgumentsToSystemBus(const char* path,
+                                          const char* interface_name,
+                                          const char* signal_name) {
+  CHECK(path);
+  CHECK(interface_name);
+  CHECK(signal_name);
+  chromeos::dbus::Proxy proxy(chromeos::dbus::GetSystemBusConnection(),
+                              path,
+                              interface_name);
+  DBusMessage* signal = ::dbus_message_new_signal(
+      path,
+      interface_name,
+      signal_name);
+  if (!signal) {
+    LOG(ERROR) << "Failed to create a signal: "
+               << "path: " << path << ", "
+               << "interface_name: " << interface_name << ", "
+               << "signal_name: " << signal_name;
+    return;
+  }
+  ::dbus_g_proxy_send(proxy.gproxy(), signal, NULL);
+  ::dbus_message_unref(signal);
+}
 
 }  // namespace dbus
 }  // namespace chromeos