Implement trait dom::bindings::conversions::JSValConvertible for f64.

src/components/script/dom/bindings/conversions.rs

@@ -85,4 +85,18 @@ impl JSValConvertible for f32 {
             Some(RUST_JSVAL_TO_DOUBLE(val) as f32)
         }
     }
-}
+}
+
+impl JSValConvertible for f64 {
+    fn to_jsval(&self) -> JSVal {
+        unsafe {
+            RUST_DOUBLE_TO_JSVAL(*self as f64)
+        }
+    }
+
+    fn from_jsval(val: JSVal) -> Option<f64> {
+        unsafe {
+            Some(RUST_JSVAL_TO_DOUBLE(val) as f64)
+        }
+    }
+}