Initial commit of alternate stylesheet support in Firebird.

browser/base/content/tabbrowser.xml

@@ -401,6 +401,10 @@
             if (updatePageReport)
               this.mCurrentBrowser.updatePageReport();
 
+            var event = document.createEvent("Events");
+            event.initEvent("DOMUpdatePageTheme", true, true);
+            this.dispatchEvent(event);
+            
             // Update the URL bar.
             var loc = this.mCurrentBrowser.currentURI;
             if (!loc)