Added RootKind and GCMethods implementation for PropertyDescriptor

Cargo.toml

@@ -2,7 +2,7 @@
 name = "mozjs"
 description = "Rust bindings to the Mozilla SpiderMonkey JavaScript engine."
 repository = "https://github.com/servo/rust-mozjs"
-version = "0.6.0"
+version = "0.6.1"
 authors = ["The Servo Project Developers"]
 build = "build.rs"
 license = "MPL-2.0"

src/rust.rs

@@ -316,6 +316,11 @@ impl RootKind for Value {
     fn rootKind() -> jsapi::RootKind { jsapi::RootKind::Value }
 }
 
+impl RootKind for PropertyDescriptor {
+    #[inline(always)]
+    fn rootKind() -> jsapi::RootKind { jsapi::RootKind::Traceable }
+}
+
 // Creates a C string literal `$str`.
 macro_rules! c_str {
     ($str:expr) => {
@@ -975,6 +980,11 @@ impl GCMethods for Value {
     }
 }
 
+impl GCMethods for PropertyDescriptor {
+    unsafe fn initial() -> PropertyDescriptor { PropertyDescriptor::default() }
+    unsafe fn post_barrier(_ : *mut PropertyDescriptor, _ : PropertyDescriptor, _ :PropertyDescriptor) {}
+}
+
 impl<T: GCMethods + Copy> Heap<T> {
     /// This creates a `Box`-wrapped Heap value. Setting a value inside Heap
     /// object triggers a barrier, referring to the Heap object location,