Set text-rendering to 'auto' when font shorthand is used in html.css.

Source/core/css/html.css

Index: Source/core/css/html.css
diff --git a/Source/core/css/html.css b/Source/core/css/html.css
index f49b8d398a743ac39b6fb8b31d52783b61f587b8..9a8052bf26a79cb858b5e1002a0bd83c4fa56fe8 100644
--- a/Source/core/css/html.css
+++ b/Source/core/css/html.css
@@ -397,6 +397,7 @@ input, textarea, keygen, select, button, meter, progress {
 input, textarea, keygen, select, button {
     margin: 0__qem;
     font: -webkit-small-control;
+    text-rendering: auto; /* FIXME: Remove when tabs work with optimizeLegibility. */
     color: initial;
     letter-spacing: normal;
     word-spacing: normal;