Fix CSSStyleDeclaration.setPropertyPriority

Before, it was a complicated no-op. (`parse_style_attribute` expects
input like `a: b; c: d;`, when given just a name it return an empty
vector.)

components/script/dom/cssstyledeclaration.rs

@@ -192,7 +192,7 @@ impl<'a> CSSStyleDeclarationMethods for &'a CSSStyleDeclaration {
         if let Some(longhand_properties) = longhand_properties {
             // Step 2.1 & 2.2 & 2.3
             if longhand_properties.iter()
-                                  .map(|longhand| self.GetPropertyPriority(longhand.clone()))
+                                  .map(|&longhand| self.GetPropertyPriority(longhand.to_owned()))
                                   .all(|priority| priority == "important") {
 
                 return "important".to_owned();
@@ -274,34 +274,25 @@ impl<'a> CSSStyleDeclarationMethods for &'a CSSStyleDeclaration {
             return Err(Error::NoModificationAllowed);
         }
 
-        // Step 2
-        let property = property.to_ascii_lowercase();
-
-        // Step 3
+        // Step 2 & 3
         if !is_supported_property(&property) {
             return Ok(());
         }
 
         // Step 4
-        let priority = priority.to_ascii_lowercase();
-        if priority != "important" && !priority.is_empty() {
-            return Ok(());
-        }
+        let priority = match &*priority {
+            "" => StylePriority::Normal,
+            p if p.eq_ignore_ascii_case("important") => StylePriority::Important,
+            _ => return Ok(()),
+        };
 
         let owner = self.owner.root();
-        let window = window_from_node(owner.r());
-        let decl_block = parse_style_attribute(&property, &window.r().get_url());
         let element = ElementCast::from_ref(owner.r());
 
-        // Step 5
-        for decl in decl_block.normal.iter() {
-            // Step 6
-            let style_priority = if priority.is_empty() {
-                StylePriority::Normal
-            } else {
-                StylePriority::Important
-            };
-            element.update_inline_style(decl.clone(), style_priority);
+        // Step 5 & 6
+        match longhands_from_shorthand(&property) {
+            Some(properties) => element.set_inline_style_property_priority(properties, priority),
+            None => element.set_inline_style_property_priority(&[&*property], priority)
         }
 
         let document = document_from_node(element);
@@ -328,21 +319,18 @@ impl<'a> CSSStyleDeclarationMethods for &'a CSSStyleDeclaration {
         // Step 3
         let value = self.GetPropertyValue(property.clone());
 
-        let longhand_properties = longhands_from_shorthand(&property);
-        match longhand_properties {
+        let owner = self.owner.root();
+        let elem = ElementCast::from_ref(owner.r());
+
+        match longhands_from_shorthand(&property) {
+            // Step 4
             Some(longhands) => {
-                // Step 4
                 for longhand in longhands.iter() {
-                    try!(self.RemoveProperty(longhand.clone()));
+                    elem.remove_inline_style_property(longhand)
                 }
             }
-
-            None => {
-                // Step 5
-                let owner = self.owner.root();
-                let elem = ElementCast::from_ref(owner.r());
-                elem.remove_inline_style_property(property)
-            }
+            // Step 5
+            None => elem.remove_inline_style_property(&property)
         }
 
         // Step 6

components/script/dom/element.rs

@@ -581,8 +581,9 @@ pub trait ElementHelpers<'a> {
     fn style_attribute(self) -> &'a DOMRefCell<Option<PropertyDeclarationBlock>>;
     fn summarize(self) -> Vec<AttrInfo>;
     fn is_void(self) -> bool;
-    fn remove_inline_style_property(self, property: DOMString);
+    fn remove_inline_style_property(self, property: &str);
     fn update_inline_style(self, property_decl: PropertyDeclaration, style_priority: StylePriority);
+    fn set_inline_style_property_priority(self, properties: &[&str], style_priority: StylePriority);
     fn get_inline_style_declaration(self, property: &Atom) -> Option<PropertyDeclaration>;
     fn get_important_inline_style_declaration(self, property: &Atom) -> Option<PropertyDeclaration>;
     fn serialize(self, traversal_scope: TraversalScope) -> Fallible<DOMString>;
@@ -652,7 +653,7 @@ impl<'a> ElementHelpers<'a> for &'a Element {
         }
     }
 
-    fn remove_inline_style_property(self, property: DOMString) {
+    fn remove_inline_style_property(self, property: &str) {
         let mut inline_declarations = self.style_attribute.borrow_mut();
         if let &mut Some(ref mut declarations) = &mut *inline_declarations {
             let index = declarations.normal
@@ -704,6 +705,28 @@ impl<'a> ElementHelpers<'a> for &'a Element {
         });
     }
 
+    fn set_inline_style_property_priority(self, properties: &[&str], style_priority: StylePriority) {
+        let mut inline_declarations = self.style_attribute().borrow_mut();
+        if let &mut Some(ref mut declarations) = &mut *inline_declarations {
+            let (from, to) = if style_priority == StylePriority::Important {
+                (&mut declarations.normal, &mut declarations.important)
+            } else {
+                (&mut declarations.normal, &mut declarations.important)
+            };
+            let from = Arc::make_unique(from);
+            let to = Arc::make_unique(to);
+            let mut new_from = Vec::new();
+            for declaration in from.drain(..) {
+                if properties.contains(&declaration.name()) {
+                    to.push(declaration)
+                } else {
+                    new_from.push(declaration)
+                }
+            }
+            mem::replace(from, new_from);
+        }
+    }
+
     fn get_inline_style_declaration(self, property: &Atom) -> Option<PropertyDeclaration> {
         let inline_declarations = self.style_attribute.borrow();
         inline_declarations.as_ref().and_then(|declarations| {