Auto merge of #8667 - asajeffrey:update-string-cache, r=SimonSapin

Update string cache

Updated string_cache to 0.2, and updated the dependencies that depend on string_cache.
Removed references to string_cache_plugin.
Import atom! and ns! from string_cache.
Replaced ns!("") by ns!().
Replaced ns!(XML) and co by ns!(xml) and co.
Replaced Atom::from_slice by Atom::from.
Replaced atom.as_slice() by &*atom.

r? @SimonSapin

<!-- Reviewable:start -->
[<img src="https://reviewable.io/review_button.png" height=40 alt="Review on Reviewable"/>](https://reviewable.io/reviews/servo/servo/8667)
<!-- Reviewable:end -->

1 files changed, 2 insertions, 2 deletions

diff --git a/components/script/script_task.rs b/components/script/script_task.rs
index 95e1c7f356f..7ceb22cbd73 100644
--- a/components/script/script_task.rs
+++ b/components/script/script_task.rs
@@ -1183,7 +1183,7 @@ impl ScriptTask {
         // Checks if the html element has reftest-wait attribute present.
         // See http://testthewebforward.org/docs/reftests.html
         let html_element = doc.GetDocumentElement();
-        let reftest_wait = html_element.map_or(false, |elem| elem.has_class(&Atom::from_slice("reftest-wait")));
+        let reftest_wait = html_element.map_or(false, |elem| elem.has_class(&Atom::from("reftest-wait")));
         if reftest_wait {
             return ScriptState::DocumentLoading;
         }
@@ -1810,7 +1810,7 @@ impl ScriptTask {
                 // Notify Constellation about the topmost anchor mouse over target.
                 for target in &*mouse_over_targets {
                     if target.is::<HTMLAnchorElement>() {
-                        let status = target.get_attribute(&ns!(""), &atom!("href"))
+                        let status = target.get_attribute(&ns!(), &atom!("href"))
                             .and_then(|href| {
                                 let value = href.value();
                                 let url = document.url();