Make compositor D-Bus service run state globally available

Add compositor available datapipe and update it from display plugin.

datapipe.c

@@ -154,6 +154,9 @@ datapipe_struct thermal_state_pipe;
 /** Heartbeat; read only */
 datapipe_struct heartbeat_pipe;
 
+/** compositor availability; read only */
+datapipe_struct compositor_available_pipe;
+
 /** lipstick availability; read only */
 datapipe_struct lipstick_available_pipe;
 
@@ -862,6 +865,8 @@ void mce_datapipe_init(void)
 		       0, GINT_TO_POINTER(THERMAL_STATE_UNDEF));
 	setup_datapipe(&heartbeat_pipe, READ_ONLY, DONT_FREE_CACHE,
 		       0, GINT_TO_POINTER(0));
+	setup_datapipe(&compositor_available_pipe, READ_ONLY, DONT_FREE_CACHE,
+		       0, GINT_TO_POINTER(FALSE));
 	setup_datapipe(&lipstick_available_pipe, READ_ONLY, DONT_FREE_CACHE,
 		       0, GINT_TO_POINTER(FALSE));
 	setup_datapipe(&dsme_available_pipe, READ_ONLY, DONT_FREE_CACHE,
@@ -931,6 +936,7 @@ void mce_datapipe_quit(void)
 	free_datapipe(&master_radio_pipe);
 	free_datapipe(&system_state_pipe);
 	free_datapipe(&heartbeat_pipe);
+	free_datapipe(&compositor_available_pipe);
 	free_datapipe(&lipstick_available_pipe);
 	free_datapipe(&dsme_available_pipe);
 	free_datapipe(&packagekit_locked_pipe);

datapipe.h

@@ -130,6 +130,7 @@ extern datapipe_struct jack_sense_pipe;
 extern datapipe_struct power_saving_mode_pipe;
 extern datapipe_struct thermal_state_pipe;
 extern datapipe_struct heartbeat_pipe;
+extern datapipe_struct compositor_available_pipe;
 extern datapipe_struct lipstick_available_pipe;
 extern datapipe_struct dsme_available_pipe;
 extern datapipe_struct packagekit_locked_pipe;

modules/display.c

@@ -5652,6 +5652,12 @@ static void mdy_stm_compositor_name_owner_changed(const char *name,
      * Turning the display on at lipstick runstate change
      * deals with both (a) and (b) */
     mdy_stm_push_target_change(MCE_DISPLAY_ON);
+
+    /* and finally broadcast within mce */
+    bool available = mdy_compositor_is_available();
+    execute_datapipe(&compositor_available_pipe,
+                     GINT_TO_POINTER(available),
+                     USE_INDATA, CACHE_INDATA);
 }
 
 /** react to systemui availability changes