Small CSS patch to take fix urlbar height expansion introduced in 337427.

bug=347085
r=ispiked
sr+branch=mconnor

browser/themes/gnomestripe/browser/browser.css

@@ -720,6 +720,7 @@ toolbar[iconsize="small"] #paste-button[disabled="true"] {
 
 #urlbar-spacer {
   visibility: hidden;
+  height: 0px;  /* We just want this widget's horizontal size behavior */
 }
 
 /* ::::: page proxy icon ::::: */