Change to chart view when opening an existing chart

src/ag-app.c

@@ -126,6 +126,7 @@ ag_app_open_chart(AgApp *app, GFile *file)
     uri = g_file_get_uri(file);
     ag_window_set_uri(AG_WINDOW(window), uri);
     g_free(uri);
+    ag_window_open_chart_tab(window);
 }
 
 static void

src/ag-window.c

@@ -813,3 +813,8 @@ ag_window_settings_save(GtkWindow *window, GSettings *settings)
     g_settings_set_int(settings, "height", height);
 }
 
+void
+ag_window_open_chart_tab(AgWindow *window)
+{
+    gtk_stack_set_visible_child_name(GTK_STACK(window->priv->stack), "chart");
+}

src/ag-window.h

@@ -45,6 +45,7 @@ void ag_window_settings_restore(GtkWindow *window,
                                 GSettings *settings);
 void ag_window_settings_save(GtkWindow *window,
                              GSettings *settings);
+void ag_window_open_chart_tab(AgWindow *window);
 
 #define AG_WINDOW_ERROR (ag_window_error_quark())
 GQuark ag_window_error_quark(void);