Handle dynamic font color change

components/script/dom/document.rs

@@ -88,6 +88,7 @@ use dom::touchevent::TouchEvent;
 use dom::touchlist::TouchList;
 use dom::treewalker::TreeWalker;
 use dom::uievent::UIEvent;
+use dom::virtualmethods::vtable_for;
 use dom::webglcontextevent::WebGLContextEvent;
 use dom::window::{ReflowReason, Window};
 use dom::windowproxy::WindowProxy;
@@ -2499,10 +2500,7 @@ impl Document {
             entry.hint.insert(RESTYLE_STYLE_ATTRIBUTE);
         }
 
-        // FIXME(emilio): This should become something like
-        // element.is_attribute_mapped(attr.local_name()).
-        if attr.local_name() == &local_name!("width") ||
-           attr.local_name() == &local_name!("height") {
+        if vtable_for(el.upcast()).attribute_is_mapped(attr) {
             entry.hint.insert(RESTYLE_SELF);
         }
 

components/script/dom/element.rs

@@ -2303,6 +2303,16 @@ impl VirtualMethods for Element {
         Some(self.upcast::<Node>() as &VirtualMethods)
     }
 
+    fn attribute_is_mapped(&self, attr: &Attr) -> bool {
+        // FIXME: This should be more fine-grained, not all elements care about these.
+        if attr.local_name() == &local_name!("width") ||
+           attr.local_name() == &local_name!("height") {
+            return true;
+        }
+
+        self.super_type().unwrap().attribute_is_mapped(attr)
+    }
+
     fn attribute_mutated(&self, attr: &Attr, mutation: AttributeMutation) {
         self.super_type().unwrap().attribute_mutated(attr, mutation);
         let node = self.upcast::<Node>();

components/script/dom/htmlfontelement.rs

@@ -3,6 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use cssparser::RGBA;
+use dom::attr::Attr;
 use dom::bindings::codegen::Bindings::HTMLFontElementBinding;
 use dom::bindings::codegen::Bindings::HTMLFontElementBinding::HTMLFontElementMethods;
 use dom::bindings::inheritance::Castable;
@@ -70,6 +71,15 @@ impl VirtualMethods for HTMLFontElement {
         Some(self.upcast::<HTMLElement>() as &VirtualMethods)
     }
 
+    fn attribute_is_mapped(&self, attr: &Attr) -> bool {
+        if attr.local_name() == &local_name!("color") {
+            return true;
+        }
+
+        // FIXME: Should also return true for `size` and `face` changes!
+        self.super_type().unwrap().attribute_is_mapped(attr)
+    }
+
     fn parse_plain_attribute(&self, name: &LocalName, value: DOMString) -> AttrValue {
         match name {
             &local_name!("face") => AttrValue::from_atomic(value.into()),

components/script/dom/virtualmethods.rs

@@ -70,6 +70,15 @@ pub trait VirtualMethods {
         }
     }
 
+    /// Returns `true` if given attribute `attr` affects style of the
+    /// given element.
+    fn attribute_is_mapped(&self, attr: &Attr) -> bool {
+        match self.super_type() {
+            Some(s) => s.attribute_is_mapped(attr),
+            None => false
+        }
+    }
+
     /// Returns the right AttrValue variant for the attribute with name `name`
     /// on this element.
     fn parse_plain_attribute(&self, name: &LocalName, value: DOMString) -> AttrValue {