API Standardise extension hooks

code/LeftAndMain.php

@@ -784,7 +784,7 @@ protected function init()
             }
         }
 
-        $this->extend('init');
+        $this->extend('onInit');
 
         // Load the editor with original user themes before overwriting
         // them with admin themes

code/LeftAndMainExtension.php

@@ -26,7 +26,7 @@ public function __construct()
         parent::__construct();
     }
 
-    public function init()
+    protected function onInit()
     {
     }
 

tests/behat/src/Extension/CannotCreateExtension.php

@@ -7,7 +7,7 @@
 
 class CannotCreateExtension extends Extension implements TestOnly
 {
-    public function canCreate()
+    protected function canCreate()
     {
         return false;
     }

tests/behat/src/Extension/CannotDeleteExtension.php

@@ -7,7 +7,7 @@
 
 class CannotDeleteExtension extends Extension implements TestOnly
 {
-    public function canDelete()
+    protected function canDelete()
     {
         return false;
     }

tests/behat/src/Extension/CannotEditExtension.php

@@ -7,7 +7,7 @@
 
 class CannotEditExtension extends Extension implements TestOnly
 {
-    public function canEdit()
+    protected function canEdit()
     {
         return false;
     }

tests/php/CMSProfileControllerTest/TestExtension.php

@@ -6,7 +6,7 @@
 
 class TestExtension extends DataExtension
 {
-    public function canEdit($member = null)
+    protected function canEdit($member = null)
     {
         return false;
     }