Auto merge of #194 - servo:from-ref-self-for-self, r=SimonSapin

Implement From<&Atom> for Atom.

Needed to do more complex stuff in selectors with local names and namespace
urls.

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Author: bors-servo

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 
 name = "string_cache"
-version = "0.6.2"  # Also update README.md when making a semver-breaking change
+version = "0.6.3"  # Also update README.md when making a semver-breaking change
 authors = [ "The Servo Project Developers" ]
 description = "A string interning library for Rust, developed as part of the Servo project."
 license = "MIT / Apache-2.0"

src/atom.rs

@@ -227,6 +227,12 @@ impl<Static: StaticAtomSet> ::precomputed_hash::PrecomputedHash for Atom<Static>
     }
 }
 
+impl<'a, Static: StaticAtomSet> From<&'a Atom<Static>> for Atom<Static> {
+    fn from(atom: &'a Self) -> Self {
+        atom.clone()
+    }
+}
+
 fn u64_hash_as_u32(h: u64) -> u32 {
     // This may or may not be great...
     ((h >> 32) ^ h) as u32