MDL-49854 core: User navigation refinements

Fixing some reported issues:
- Removing unnecessary conditional include
- Require login in grade/report/mygrades.php
- Remove unnecessary defined('MOODLE_INTERNAL') call
- Fixing context_header::__construct $imagedata param type

course/user.php

@@ -175,8 +175,8 @@ switch ($mode) {
 
         break;
     default:
-        // can not be reached ;-)
-        // But just incase let's not break the navigation.
+        // It's unlikely to reach this piece of code, as the mode is never empty and it sets mode as grade in most of the cases.
+        // Display the page header to avoid breaking the navigation. A course/user.php review will be done in MDL-49939.
         echo $OUTPUT->header();
 }
 

grade/report/mygrades.php

@@ -25,8 +25,10 @@
 require_once('../../config.php');
 require_once($CFG->dirroot . '/user/lib.php');
 
-defined('MOODLE_INTERNAL') || die();
-
+require_login(null, false);
+if (isguestuser()) {
+    throw new require_login_exception('Guests are not allowed here.');
+}
 // Get the url to redirect to.
 $url = user_mygrades_url();
 // Redirect to that page.

lib/outputcomponents.php

@@ -3095,7 +3095,7 @@ class context_header implements renderable {
      */
     public $headinglevel;
     /**
-     * @var string $imagedata HTML for the Image for the header.
+     * @var string|null $imagedata HTML code for the picture in the page header.
      */
     public $imagedata;
     /**
@@ -3113,7 +3113,7 @@ class context_header implements renderable {
      *
      * @param string $heading Main heading data.
      * @param int $headinglevel Main heading 'h' tag level.
-     * @param object $imagedata Information needed to include a picture in the header.
+     * @param string|null $imagedata HTML code for the picture in the page header.
      * @param string $additionalbuttons Buttons for the header e.g. Messaging button for the user header.
      */
     public function __construct($heading = null, $headinglevel = 1, $imagedata = null, $additionalbuttons = null) {

user/classes/output/myprofile/manager.php

@@ -25,6 +25,9 @@
 namespace core_user\output\myprofile;
 defined('MOODLE_INTERNAL') || die();
 
+global $CFG;
+require_once($CFG->libdir . "/myprofilelib.php");
+
 /**
  * Defines MAnager class for myprofile navigation tree.
  *
@@ -44,18 +47,10 @@ class manager {
      * @return tree Fully build tree to be rendered on my profile page.
      */
     public static function build_tree($user, $iscurrentuser, $course = null) {
-        global $CFG;
         $tree = new tree();
 
         // Add core nodes.
-        $file = $CFG->libdir . "/myprofilelib.php";
-        if (is_readable($file)) {
-            require_once($file);
-            $function = "core_myprofile_navigation";
-            if (function_exists($function)) {
-                $function($tree, $user, $iscurrentuser, $course);
-            }
-        }
+        core_myprofile_navigation($tree, $user, $iscurrentuser, $course);
 
         // Core components.
         $components = \core_component::get_core_subsystems();