Add parsing of double values in style attributes

components/script/dom/htmlfontelement.rs

@@ -150,8 +150,8 @@ pub fn parse_legacy_font_size(mut input: &str) -> Option<&'static str> {
 
     // Steps 6, 7, 8
     let mut value = match read_numbers(input_chars) {
-        Some(v) => v,
-        None => return None,
+        (Some(v), _) => v,
+        (None, _) => return None,
     };
 
     // Step 9

components/script/dom/htmltableelement.rs

@@ -410,7 +410,7 @@ impl VirtualMethods for HTMLTableElement {
             }
             atom!("cellspacing") => {
                 self.cellspacing.set(mutation.new_value(attr).and_then(|value| {
-                    parse_unsigned_integer(value.chars())
+                    parse_unsigned_integer(value.chars()).ok()
                 }));
             },
             _ => {},