Bug 1490952 - Align <tabs> default and override styles on Mac. r=mikedeboer

browser/themes/osx/browser.css

@@ -695,6 +695,10 @@ html|input.urlbar-input {
 
 #tabbrowser-tabs {
   -moz-box-align: stretch;
+  padding-left: 0;
+  padding-right: 0;
+  margin-bottom: 0;
+  position: static;
 }
 
 /**

toolkit/themes/osx/global/in-content/common.css

@@ -8,6 +8,7 @@
 xul|tabs {
   padding-right: 0;
   padding-left: 0;
+  position: static;
 }
 
 xul|tab[visuallyselected] {

toolkit/themes/osx/global/tabbox.css

@@ -22,9 +22,6 @@ tabpanels {
 tabs {
   -moz-box-align: center;
   font: menu;
-}
-
-tabbox > tabs {
   padding: 0 10px;
   margin-bottom: -12px;
   position: relative;