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/htmltablecellelement.rs

@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::attr::{Attr, AttrHelpers, AttrValue};
+use dom::attr::{Attr, AttrValue};
 use dom::bindings::codegen::Bindings::HTMLTableCellElementBinding::HTMLTableCellElementMethods;
 use dom::bindings::codegen::InheritTypes::{HTMLElementCast, HTMLTableCellElementDerived};
 use dom::document::Document;
@@ -80,22 +80,17 @@ impl<'a> HTMLTableCellElementMethods for &'a HTMLTableCellElement {
     make_uint_setter!(SetColSpan, "colspan");
 }
 
-pub trait HTMLTableCellElementHelpers {
-    fn get_background_color(self) -> Option<RGBA>;
-    fn get_colspan(self) -> Option<u32>;
-    fn get_width(self) -> LengthOrPercentageOrAuto;
-}
 
-impl<'a> HTMLTableCellElementHelpers for &'a HTMLTableCellElement {
-    fn get_background_color(self) -> Option<RGBA> {
+impl HTMLTableCellElement {
+    pub fn get_background_color(&self) -> Option<RGBA> {
         self.background_color.get()
     }
 
-    fn get_colspan(self) -> Option<u32> {
+    pub fn get_colspan(&self) -> Option<u32> {
         self.colspan.get()
     }
 
-    fn get_width(self) -> LengthOrPercentageOrAuto {
+    pub fn get_width(&self) -> LengthOrPercentageOrAuto {
         self.width.get()
     }
 }