Allow always logging tofu detection

This commit allows to log tofu detection always,
even if the rest of the webfonts library is not loaded.

By default this is disabled.

To enable it, set the variable $wgULSTofuLoggingChance
to a number between 0 and 100, indicating the chance of it
getting logged. The idea of the lottery is that even a partial
sample can be useful.

Change-Id: Ia08fe0de348b7eebfa95498a6be58ae41608ba3b

UniversalLanguageSelector.php

@@ -136,6 +136,25 @@ $GLOBALS['wgULSPosition'] = 'personal';
  */
 $GLOBALS['wgULSEventLogging'] = false;
 
+/**
+ * How frequently to run tofu detection for all languages and to log them.
+ * This must be a number between 0 and 100, which signifies the percentage
+ * of pages for which this will be done. If it's 100, then it will be
+ * done for all pages. If it's 20, then it will be done on 20% of pages.
+ * The default is not to do it on any pages.
+ * @since 2014.04
+ */
+$GLOBALS['wgULSTofuLoggingChance'] = 0;
+
+/**
+ * If tofu detection for all languages is enabled, and this value is non-zero
+ * this specifies the maximum time in milliseconds that the tofu detection
+ * is allowed to run before it's forced to stop.
+ * The default is 0 - not to force it to stop.
+ * @since 2014.04
+ */
+$GLOBALS['wgULSTofuLoggingMaxTime'] = 0;
+
 /**
  * Array of jQuery selectors of elements on which IME should be enabled.
  *