MDL-34472 libraries: Remove usage of get_context_instance() from core

lib/accesslib.php

@@ -717,7 +717,7 @@ function has_capability_in_accessdata($capability, context $context, array &$acc
  * @see has_capability()
  *
  * @param string $capability the name of the capability to check. For example mod/forum:view
- * @param context $context the context to check the capability in. You normally get this with {@link get_context_instance}.
+ * @param context $context the context to check the capability in. You normally get this with context_xxxx::instance().
  * @param int $userid A user id. By default (null) checks the permissions of the current user.
  * @param bool $doanything If false, ignore effect of admin role assignment
  * @param string $errormessage The error string to to user. Defaults to 'nopermissions'.

lib/pagelib.php

@@ -899,7 +899,7 @@ class moodle_page {
     /**
      * Set the main context to which this page belongs.
      *
-     * @param context $context a context object, normally obtained with get_context_instance.
+     * @param context $context a context object. You normally get this with context_xxxx::instance().
      */
     public function set_context($context) {
         if ($context === null) {

mod/assign/feedback/offline/locallib.php

@@ -80,7 +80,7 @@ class assign_feedback_offline extends assign_feedback_plugin {
 
         $gradeimporter = new assignfeedback_offline_grade_importer($importid, $this->assignment);
 
-        $context = get_context_instance(CONTEXT_USER, $USER->id);
+        $context = context_user::instance($USER->id);
         $fs = get_file_storage();
         if (!$files = $fs->get_area_files($context->id, 'user', 'draft', $draftid, 'id DESC', false)) {
             redirect(new moodle_url('view.php',

user/lib.php

@@ -527,11 +527,11 @@ function user_get_user_details_courses($user) {
  */
 function can_view_user_details_cap($user, $course = null) {
     // Check $USER has the capability to view the user details at user context.
-    $usercontext = get_context_instance(CONTEXT_USER, $user->id);
+    $usercontext = context_user::instance($user->id);
     $result = has_capability('moodle/user:viewdetails', $usercontext);
     // Otherwise can $USER see them at course context.
     if (!$result && !empty($course)) {
-        $context = get_context_instance(CONTEXT_COURSE, $course->id);
+        $context = context_course::instance($course->id);
         $result = has_capability('moodle/user:viewdetails', $context);
     }
     return $result;