feat(headers): add Content-Location header

Closes #870

src/header/common/content_location.rs

@@ -0,0 +1,44 @@
+header! {
+    /// `Content-Location` header, defined in
+    /// [RFC7231](https://tools.ietf.org/html/rfc7231#section-3.1.4.2)
+    ///
+    /// The header can be used by both the client in requests and the server
+    /// in resposes with different semantics. Client sets `Content-Location`
+    /// to refer to the URI where original representation of the body was
+    /// obtained.
+    ///
+    /// In responses `Content-Location` represents URI for the representation
+    /// that was content negotiated, created or for the response payload.
+    ///
+    /// # ABNF
+    /// ```plain
+    /// Content-Location = absolute-URI / partial-URI
+    /// ```
+    ///
+    /// # Example values
+    /// * `/hypertext/Overview.html`
+    /// * `http://www.example.org/hypertext/Overview.html`
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use hyper::header::{Headers, ContentLocation};
+    ///
+    /// let mut headers = Headers::new();
+    /// headers.set(ContentLocation("/hypertext/Overview.html".to_owned()));
+    /// ```
+    /// ```
+    /// use hyper::header::{Headers, ContentLocation};
+    ///
+    /// let mut headers = Headers::new();
+    /// headers.set(ContentLocation("http://www.example.org/hypertext/Overview.html".to_owned()));
+    /// ```
+    // TODO: use URL
+    (ContentLocation, "Content-Location") => [String]
+
+    test_content_location {
+        test_header!(partial_query, vec![b"/hypertext/Overview.html?q=tim"]);
+
+        test_header!(absolute, vec![b"http://www.example.org/hypertext/Overview.html"]);
+    }
+}