Revert "Pass uselang=user to the API instead of figuring it out client side"

This breaks pages using ?uselang=xx where "xx" is not
the user's language.

This reverts commit 0919b01e75.

Bug: T103935
Change-Id: I219810451b991cef88bac62cf880bfda6f98e930

modules/overlay/ext.echo.overlay.js

@@ -2,6 +2,8 @@
 ( function ( $, mw ) {
 	'use strict';
 
+	var useLang = mw.config.get( 'wgUserLanguage' );
+
 	function EchoOverlay( apiResultNotifications ) {
 		this.api = mw.echo.overlay.api;
 		// set internal properties
@@ -82,7 +84,7 @@
 			if ( this.unread.length ) {
 				data = {
 					action: 'echomarkread',
-					uselang: 'user'
+					uselang: useLang
 				};
 				if ( id ) {
 					// If id is given mark that as read otherwise use all unread messages
@@ -458,7 +460,7 @@
 				notformat: 'flyout',
 				notlimit: this.notificationLimit,
 				notprop: 'index|list|count',
-				uselang: 'user'
+				uselang: useLang
 			};
 
 			return this.api.get( apiData ).then( function ( result ) {

modules/special/ext.echo.special.js

@@ -1,5 +1,6 @@
 ( function ( $, mw ) {
 	'use strict';
+	var useLang = mw.config.get( 'wgUserLanguage' );
 
 	mw.echo.special = {
 
@@ -67,7 +68,7 @@
 					notprop: 'index|list',
 					notcontinue: this.notcontinue,
 					notlimit: mw.config.get( 'wgEchoDisplayNum' ),
-					uselang: 'user'
+					uselang: useLang
 				};
 
 			api.get( apiData ).done( function ( result ) {
@@ -129,7 +130,7 @@
 			api.postWithToken( 'edit', {
 				action: 'echomarkread',
 				list: unread.join( '|' ),
-				uselang: 'user'
+				uselang: useLang
 			} ).done( function ( result ) {
 				// update the badge if the link is enabled
 				if ( result.query.echomarkread.count !== undefined &&