Make a bunch of types 'static.

The reasoning for this is explained in a comment in the next patch.

MozReview-Commit-ID: FQgDY77mg3B

components/style/gecko_bindings/sugar/ownership.rs

@@ -11,7 +11,7 @@ use std::ptr;
 use stylearc::Arc;
 
 /// Indicates that a given Servo type has a corresponding Gecko FFI type.
-pub unsafe trait HasFFI : Sized {
+pub unsafe trait HasFFI : Sized + 'static {
     /// The corresponding Gecko type that this rust type represents.
     ///
     /// See the examples in `components/style/gecko/conversions.rs`.

components/style/properties/properties.mako.rs

@@ -2193,7 +2193,7 @@ pub fn get_writing_mode(inheritedbox_style: &style_structs::InheritedBox) -> Wri
 }
 
 /// A reference to a style struct of the parent, or our own style struct.
-pub enum StyleStructRef<'a, T: 'a> {
+pub enum StyleStructRef<'a, T: 'static> {
     /// A borrowed struct from the parent, for example, for inheriting style.
     Borrowed(&'a Arc<T>),
     /// An owned struct, that we've already mutated.