Clean up unused constants and outdated comments

Change-Id: If6462e3a67726234abe62fd4d02a5d19ff4f02e0

includes/Constants.php

@@ -22,8 +22,7 @@ final class Constants {
 	 */
 	public const SKIN_NAME_LEGACY = 'vector';
 
-	// These are tightly coupled to PREF_KEY_SKIN_VERSION and skin.json's configs. See skin.json for
-	// documentation.
+	// These are used to provide different default skin for new users.
 	/**
 	 * @var string
 	 */
@@ -43,6 +42,7 @@ final class Constants {
 	 */
 	public const SERVICE_FEATURE_MANAGER = 'Vector.FeatureManager';
 
+	// These are tightly coupled to skin.json's configs. See skin.json for documentation.
 	/**
 	 * @var string
 	 */
@@ -66,11 +66,6 @@ final class Constants {
 	 */
 	public const PREF_KEY_SKIN = 'skin';
 
-	/**
-	 * @var string
-	 */
-	public const PREF_KEY_SKIN_VERSION = 'VectorSkinVersion';
-
 	/**
 	 * @var string
 	 */

includes/Hooks.php

@@ -679,8 +679,6 @@ class Hooks {
 	 * Gets whether the current skin version is the legacy version.
 	 * Should mirror SkinVector::isLegacy
 	 *
-	 * @see VectorServices::getFeatureManager
-	 *
 	 * @param string $skinName hint that can be used to detect modern vector.
 	 * @return bool
 	 */

tests/phpunit/integration/VectorHooksTest.php

@@ -27,9 +27,6 @@ use Vector\SkinVectorLegacy;
  * @coversDefaultClass \Vector\Hooks
  */
 class VectorHooksTest extends MediaWikiIntegrationTestCase {
-	private const HIDE_IF = [ '!==', 'skin', Constants::SKIN_NAME_LEGACY ];
-
-	private const SKIN_PREFS_SECTION = 'rendering/skin/skin-prefs';
 
 	/**
 	 * @param bool $excludeMainPage