Bug 1310587 - [DateTime Input] Make background of reset button in input box transparent. r=mconley

toolkit/content/widgets/datetimebox.css

@@ -34,6 +34,7 @@
 
 .datetime-reset-button {
   background-image: url(chrome://global/skin/icons/input-clear.svg);
+  background-color: transparent;
   background-repeat: no-repeat;
   background-size: 12px, 12px;
   border: none;