Use $this->output/page instead of globals in renderer

renderer.php

@@ -36,8 +36,7 @@ class tool_lifecycle_renderer extends plugin_renderer_base {
      * Write the page footer
      */
     public function footer() {
-        global $OUTPUT;
-        echo $OUTPUT->footer();
+        echo $this->output->footer();
     }
 
     /**
@@ -46,12 +45,11 @@ class tool_lifecycle_renderer extends plugin_renderer_base {
      * @param string $title optional page title.
      */
     public function header($title = null) {
-        global $OUTPUT, $PAGE;
-        echo $OUTPUT->header();
+        echo $this->output->header();
         if ($title) {
-            echo $OUTPUT->heading($title);
+            echo $this->output->heading($title);
         } else {
-            echo $OUTPUT->heading($PAGE->heading);
+            echo $this->output->heading($this->page->heading);
         }
     }