Switch to data_url::mime for document content type (#36522)

The data_url Mime parser has a more conformant behavior in most cases,
including dealing with charsets.

Testing: wpt expectations with new passes are updated.

Signed-off-by: webbeef <me@webbeef.org>

components/script/mime.rs

@@ -0,0 +1,62 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use data_url::mime::Mime;
+use headers::ContentType;
+
+pub(crate) static APPLICATION: &str = "application";
+pub(crate) static CHARSET: &str = "charset";
+pub(crate) static HTML: &str = "html";
+pub(crate) static TEXT: &str = "text";
+pub(crate) static XML: &str = "xml";
+
+/// Convenience methods to make the data_url Mime type more ergonomic.
+pub(crate) trait MimeExt {
+    /// Creates a new Mime from type and subtype, without any parameter.
+    fn new(type_: &str, subtype: &str) -> Self;
+
+    /// Checks that this Mime matches a given type and subtype, ignoring
+    /// parameters.
+    fn matches(&self, type_: &str, subtype: &str) -> bool;
+
+    /// Checks that the subtype has a given suffix.
+    /// Eg. image/svg+xml has the the xml suffix.
+    fn has_suffix(&self, suffix: &str) -> bool;
+
+    /// TODO: replace by a derive on data_url.
+    fn clone(&self) -> Self;
+
+    /// Build a Mime from the value of a Content-Type header.
+    fn from_ct(ct: ContentType) -> Self;
+}
+
+impl MimeExt for Mime {
+    fn new(type_: &str, subtype: &str) -> Self {
+        Mime {
+            type_: type_.into(),
+            subtype: subtype.into(),
+            parameters: vec![],
+        }
+    }
+
+    fn matches(&self, type_: &str, subtype: &str) -> bool {
+        self.type_ == type_ && self.subtype == subtype
+    }
+
+    fn has_suffix(&self, suffix: &str) -> bool {
+        self.subtype.ends_with(&format!("+{}", suffix))
+    }
+
+    fn clone(&self) -> Self {
+        Self {
+            type_: self.type_.clone(),
+            subtype: self.subtype.clone(),
+            parameters: self.parameters.clone(),
+        }
+    }
+
+    fn from_ct(ct: ContentType) -> Self {
+        ct.to_string().parse().unwrap()
+    }
+}