Provide action to switch to the last workspace (#229)

data/org.pantheon.desktop.gala.gschema.xml.in

@@ -9,6 +9,7 @@
 		<value nick="custom-command" value="5" />
 		<value nick="window-overview" value="6" />
 		<value nick="window-overview-all" value="7" />
+		<value nick="switch-to-workspace-last" value="8" />
 	</enum>
 	<enum id="GalaWindowOverviewType">
 		<value nick='grid' value='0'/>

lib/WindowManager.vala

@@ -26,7 +26,8 @@ namespace Gala
 		OPEN_LAUNCHER,
 		CUSTOM_COMMAND,
 		WINDOW_OVERVIEW,
-		WINDOW_OVERVIEW_ALL
+		WINDOW_OVERVIEW_ALL,
+		SWITCH_TO_WORKSPACE_LAST
 	}
 
 	/**

src/WindowManager.vala

@@ -684,6 +684,10 @@ namespace Gala
 						window_overview.open (hints);
 					}
 					break;
+				case ActionType.SWITCH_TO_WORKSPACE_LAST:
+					var workspace = screen.get_workspace_by_index (screen.get_n_workspaces () - 1);
+					workspace.activate (display.get_current_time ());
+					break;
 				default:
 					warning ("Trying to run unknown action");
 					break;