Remove helper traits

Now that JSRef<T> is gone, there is no need to have helper traits.

On components/script/*.rs:

    # Remove imports.
    /^ *use dom::[a-z]+::\{.*Helpers/ {
        s/\{(Raw[^L]|[^L][^a])[a-zA-Z]+Helpers, /\{/
        s/, (Raw[^L]|[^L][^a])[a-zA-Z]+Helpers([,}])/\2/g
        s/\{([a-zA-Z]+)\}/\1/
        /\{\}/d
        s/::self;$/;/
    }
    /^ *use dom::[a-z]+::\{?(Raw[^L]|[^L][^a])[a-zA-Z]+Helpers\}?;$/d

On components/script/dom/*.rs:

    # Ignore layout things.
    /^(pub )?(impl|trait).*Layout.* \{/,/^}$/ { P; D; }

    # Delete helpers traits.
    /^(pub )?trait ([^L][^ ]|L[^a])[^ ]+Helpers(<'a>)? \{$/,/^\}$/D

    # Patch private helpers.
    /^impl.*Private.*Helpers/,/^\}$/ {
        s/^impl<'a> Private([^L][^ ]|L[^a])[^ ]+Helpers(<'a>)? for &'a ([^ ]+) \{$/impl \3 {/
        /^ *(unsafe )?fn .*\(self.*[<&]'a/ {
            s/&'a /\&/g
            s/<'a, /</g
        }
        /^ *(unsafe )?fn /s/\(self([,)])/\(\&self\1/
    }

    # Patch public helpers.
    /^impl.*Helpers/,/^\}$/ {
        s/^impl(<'a>)? ([^L][^ ]|L[^a])[^ ]+Helpers(<'a>)? for (&'a )?([^ ]+) \{$/impl \5 {/
        /^ *(unsafe )?fn .*\(self.*[<&]'a/ {
            s/&'a /\&/g
            s/<'a, /</g
        }
        /^ *(unsafe )?fn .*\(&?self[,)]/s/(unsafe )?fn/pub &/
        /^ *pub (unsafe )?fn /s/\(self([,)])/\(\&self\1/
    }

The few error cases were then fixed by hand.

components/script/dom/characterdata.rs

@@ -15,7 +15,7 @@ use dom::bindings::js::{LayoutJS, Root};
 use dom::document::Document;
 use dom::element::Element;
 use dom::eventtarget::{EventTarget, EventTargetTypeId};
-use dom::node::{Node, NodeHelpers, NodeTypeId};
+use dom::node::{Node, NodeTypeId};
 
 use util::str::{DOMString, slice_chars};
 
@@ -157,18 +157,14 @@ pub enum CharacterDataTypeId {
     ProcessingInstruction,
 }
 
-pub trait CharacterDataHelpers<'a> {
-    fn data(self) -> Ref<'a, DOMString>;
-    fn append_data(self, data: &str);
-}
 
-impl<'a> CharacterDataHelpers<'a> for &'a CharacterData {
+impl CharacterData {
     #[inline]
-    fn data(self) -> Ref<'a, DOMString> {
+    pub fn data(&self) -> Ref<DOMString> {
         self.data.borrow()
     }
     #[inline]
-    fn append_data(self, data: &str) {
+    pub fn append_data(&self, data: &str) {
         self.data.borrow_mut().push_str(data)
     }
 }