Convert various helper traits from &JSRef to JSRef

I converted them all with a few exceptions:

- Methods that were used by trait objects, since trait objects don't
  work with `self` methods.
- Methods that take an &'b JSRef<'a, T> and return an &'b. In reality,
  many (all?) could return an &'a instead, but this isn't allowed by the
  Deref trait.
- Methods that internally rely on the same issue with Deref.
- I left out the traits involved in layout entirely, even though not all
  of their methods suffer from one of the above problems.

There will probably be solutions to all of these problems in the future.

components/script/dom/document.rs

@@ -150,16 +150,16 @@ impl CollectionFilter for AppletsFilter {
 
 pub trait DocumentHelpers {
     fn url<'a>(&'a self) -> &'a Url;
-    fn quirks_mode(&self) -> QuirksMode;
-    fn set_quirks_mode(&self, mode: QuirksMode);
-    fn set_last_modified(&self, value: DOMString);
-    fn set_encoding_name(&self, name: DOMString);
-    fn content_changed(&self);
-    fn damage_and_reflow(&self, damage: DocumentDamageLevel);
-    fn wait_until_safe_to_modify_dom(&self);
-    fn unregister_named_element(&self, to_unregister: JSRef<Element>, id: DOMString);
-    fn register_named_element(&self, element: JSRef<Element>, id: DOMString);
-    fn load_anchor_href(&self, href: DOMString);
+    fn quirks_mode(self) -> QuirksMode;
+    fn set_quirks_mode(self, mode: QuirksMode);
+    fn set_last_modified(self, value: DOMString);
+    fn set_encoding_name(self, name: DOMString);
+    fn content_changed(self);
+    fn damage_and_reflow(self, damage: DocumentDamageLevel);
+    fn wait_until_safe_to_modify_dom(self);
+    fn unregister_named_element(self, to_unregister: JSRef<Element>, id: DOMString);
+    fn register_named_element(self, element: JSRef<Element>, id: DOMString);
+    fn load_anchor_href(self, href: DOMString);
 }
 
 impl<'a> DocumentHelpers for JSRef<'a, Document> {
@@ -167,37 +167,37 @@ impl<'a> DocumentHelpers for JSRef<'a, Document> {
         &*self.url
     }
 
-    fn quirks_mode(&self) -> QuirksMode {
+    fn quirks_mode(self) -> QuirksMode {
         self.quirks_mode.deref().get()
     }
 
-    fn set_quirks_mode(&self, mode: QuirksMode) {
+    fn set_quirks_mode(self, mode: QuirksMode) {
         self.quirks_mode.deref().set(mode);
     }
 
-    fn set_last_modified(&self, value: DOMString) {
+    fn set_last_modified(self, value: DOMString) {
         *self.last_modified.deref().borrow_mut() = Some(value);
     }
 
-    fn set_encoding_name(&self, name: DOMString) {
+    fn set_encoding_name(self, name: DOMString) {
         *self.encoding_name.deref().borrow_mut() = name;
     }
 
-    fn content_changed(&self) {
+    fn content_changed(self) {
         self.damage_and_reflow(ContentChangedDocumentDamage);
     }
 
-    fn damage_and_reflow(&self, damage: DocumentDamageLevel) {
+    fn damage_and_reflow(self, damage: DocumentDamageLevel) {
         self.window.root().damage_and_reflow(damage);
     }
 
-    fn wait_until_safe_to_modify_dom(&self) {
+    fn wait_until_safe_to_modify_dom(self) {
         self.window.root().wait_until_safe_to_modify_dom();
     }
 
 
     /// Remove any existing association between the provided id and any elements in this document.
-    fn unregister_named_element(&self,
+    fn unregister_named_element(self,
                                 to_unregister: JSRef<Element>,
                                 id: DOMString) {
         let mut idmap = self.idmap.deref().borrow_mut();
@@ -218,7 +218,7 @@ impl<'a> DocumentHelpers for JSRef<'a, Document> {
     }
 
     /// Associate an element present in this document with the provided id.
-    fn register_named_element(&self,
+    fn register_named_element(self,
                               element: JSRef<Element>,
                               id: DOMString) {
         assert!({
@@ -261,7 +261,7 @@ impl<'a> DocumentHelpers for JSRef<'a, Document> {
         idmap.insert(id, elements);
     }
 
-    fn load_anchor_href(&self, href: DOMString) {
+    fn load_anchor_href(self, href: DOMString) {
         let window = self.window.root();
         window.load_url(href);
     }
@@ -329,12 +329,12 @@ impl Reflectable for Document {
 }
 
 trait PrivateDocumentHelpers {
-    fn createNodeList(&self, callback: |node: JSRef<Node>| -> bool) -> Temporary<NodeList>;
-    fn get_html_element(&self) -> Option<Temporary<HTMLHtmlElement>>;
+    fn createNodeList(self, callback: |node: JSRef<Node>| -> bool) -> Temporary<NodeList>;
+    fn get_html_element(self) -> Option<Temporary<HTMLHtmlElement>>;
 }
 
 impl<'a> PrivateDocumentHelpers for JSRef<'a, Document> {
-    fn createNodeList(&self, callback: |node: JSRef<Node>| -> bool) -> Temporary<NodeList> {
+    fn createNodeList(self, callback: |node: JSRef<Node>| -> bool) -> Temporary<NodeList> {
         let window = self.window.root();
 
         match self.GetDocumentElement().root() {
@@ -355,7 +355,7 @@ impl<'a> PrivateDocumentHelpers for JSRef<'a, Document> {
 
     }
 
-    fn get_html_element(&self) -> Option<Temporary<HTMLHtmlElement>> {
+    fn get_html_element(self) -> Option<Temporary<HTMLHtmlElement>> {
         self.GetDocumentElement().root().filtered(|root| {
             let root: JSRef<Node> = NodeCast::from_ref(**root);
             root.type_id() == ElementNodeTypeId(HTMLHtmlElementTypeId)