Bug 1407185 - Remove extra toolbar drag space on osx. r=johannh

MozReview-Commit-ID: 5zfeYpt0Ceh

--HG--
extra : rebase_source : 8f4d9300be0455b5a4b947742e9ad75d78023cf9

browser/themes/osx/browser.css

@@ -89,8 +89,12 @@
   margin-left: 7px;
 }
 
-.titlebar-placeholder[type="fullscreen-button"] {
-  margin-right: 4px;
+/* The fullscreen button doesnt show on Yosemite(10.10) or above so dont give it a
+   border there */
+@media not all and (-moz-mac-yosemite-theme) {
+  .titlebar-placeholder[type="fullscreen-button"] {
+    margin-right: 4px;
+  }
 }
 
 #main-window:not(:-moz-lwtheme) > #titlebar {