eventlogger module for ULS

Separating event logging out of ULS functionality. Event logging
is now loosely coupled with ULS. ULS core modules can emit an event
whenever EventLogging is required. The eventlogger module will act
on the event if configured.

Change-Id: I59dfcfb25c1acb85376b56239f2355ee7c4aff1e

resources/js/ext.uls.init.js

@@ -33,8 +33,7 @@
 
 	var jsonLoader = null,
 		initialized = false,
-		currentLang = mw.config.get( 'wgUserLanguage' ),
-		logEventQueue = $.Callbacks( 'memory once' );
+		currentLang = mw.config.get( 'wgUserLanguage' );
 
 	mw.uls = mw.uls || {};
 	mw.uls.previousLanguagesCookie = 'uls-previous-languages';
@@ -47,11 +46,7 @@
 	mw.uls.changeLanguage = function ( language ) {
 		var uri = new mw.Uri( window.location.href );
 
-		mw.uls.logEvent( {
-			action: 'language-change',
-			context: 'interface',
-			interfaceLanguage: language
-		}, 500 ).always( function () {
+		mw.hook( 'mw.uls.interface.language.change' ).fire( language, function () {
 			uri.extend( {
 				setlang: language
 			} );
@@ -170,39 +165,6 @@
 		return !$.client.test( blacklist, null, true );
 	}
 
-	/**
-	 * Local wrapper for 'mw.eventLog.logEvent' which handles default params
-	 * and ensures the correct schema is loaded.
-	 *
-	 * @param {Object} event Event action and optional fields
-	 * @param {int} [timeout] Fail the request if it is not completed within
-	 *   the specified timeout. Can be use for example to log actions that
-	 *   cause the browser to navigate to other pages.
-	 * @return {jQuery.Promise} jQuery Promise object for the logging call
-	 * @since 2013.07
-	 * @see https://meta.wikimedia.org/wiki/Schema:UniversalLanguageSelector
-	 */
-	mw.uls.logEvent = function ( event, timeout ) {
-		// We need to create our own deferred for two reasons:
-		//  - logEvent might not be executed immediately
-		//  - we cannot reject a promise returned by it
-		// So we proxy the original promises status updates
-		// and register our timeout if requested (for links).
-		var deferred = $.Deferred();
-
-		logEventQueue.add( function () {
-			mw.eventLog.logEvent( 'UniversalLanguageSelector', event )
-				.done( deferred.resolve )
-				.fail( deferred.reject );
-		} );
-
-		if ( timeout !== undefined ) {
-			window.setTimeout( deferred.reject, timeout );
-		}
-
-		return deferred.promise();
-	};
-
 	/**
 	 * Initialize ULS front-end and its i18n.
 	 *
@@ -224,20 +186,6 @@
 			return;
 		}
 
-		// If EventLogging integration is enabled, set event defaults and make the
-		// the function call event logging with correct schema.
-		if ( mw.config.get( 'wgULSEventLogging' ) ) {
-			mw.loader.using( 'schema.UniversalLanguageSelector', function () {
-				mw.eventLog.setDefaults( 'UniversalLanguageSelector', {
-					version: 1,
-					token: mw.user.id(),
-					contentLanguage: mw.config.get( 'wgContentLanguage' ),
-					interfaceLanguage: currentLang
-				} );
-				logEventQueue.fire();
-			} );
-		}
-
 		/*
 		 * The 'als' is used in a non-standard way in MediaWiki -
 		 * it may be used to represent the Allemanic language,