Auto merge of #19972 - paavininanda:Issue16483, r=jdm

replaced content_type from DOCString to Mime

Replaced content_type from DomString to Mime

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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #16483 (https://github.com/servo/servo/issues/16483).

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- [x] These changes do not require tests because they make changes to already existing files

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components/script/dom/document.rs

@@ -98,6 +98,7 @@ use ipc_channel::ipc::{self, IpcSender};
 use js::jsapi::{JSContext, JSObject, JSRuntime};
 use js::jsapi::JS_GetRuntime;
 use metrics::{InteractiveFlag, InteractiveMetrics, InteractiveWindow, ProfilerMetadataFactory, ProgressiveWebMetric};
+use mime::{Mime, TopLevel, SubLevel};
 use msg::constellation_msg::{BrowsingContextId, Key, KeyModifiers, KeyState, TopLevelBrowsingContextId};
 use net_traits::{FetchResponseMsg, IpcSend, ReferrerPolicy};
 use net_traits::CookieSource::NonHTTP;
@@ -235,7 +236,8 @@ pub struct Document {
     node: Node,
     window: Dom<Window>,
     implementation: MutNullableDom<DOMImplementation>,
-    content_type: DOMString,
+    #[ignore_malloc_size_of = "type from external crate"]
+    content_type: Mime,
     last_modified: Option<String>,
     encoding: Cell<&'static Encoding>,
     has_browsing_context: bool,
@@ -2195,7 +2197,7 @@ impl Document {
                          url: Option<ServoUrl>,
                          origin: MutableOrigin,
                          is_html_document: IsHTMLDocument,
-                         content_type: Option<DOMString>,
+                         content_type: Option<Mime>,
                          last_modified: Option<String>,
                          activity: DocumentActivity,
                          source: DocumentSource,
@@ -2220,12 +2222,12 @@ impl Document {
             has_browsing_context: has_browsing_context == HasBrowsingContext::Yes,
             implementation: Default::default(),
             content_type: match content_type {
-                Some(string) => string,
-                None => DOMString::from(match is_html_document {
+                Some(mime_data) => mime_data,
+                None => Mime::from(match is_html_document {
                     // https://dom.spec.whatwg.org/#dom-domimplementation-createhtmldocument
-                    IsHTMLDocument::HTMLDocument => "text/html",
+                    IsHTMLDocument::HTMLDocument => Mime(TopLevel::Text, SubLevel::Html, vec![]),
                     // https://dom.spec.whatwg.org/#concept-document-content-type
-                    IsHTMLDocument::NonHTMLDocument => "application/xml",
+                    IsHTMLDocument::NonHTMLDocument => Mime(TopLevel::Application, SubLevel::Xml, vec![]),
                 }),
             },
             last_modified: last_modified,
@@ -2337,7 +2339,7 @@ impl Document {
                url: Option<ServoUrl>,
                origin: MutableOrigin,
                doctype: IsHTMLDocument,
-               content_type: Option<DOMString>,
+               content_type: Option<Mime>,
                last_modified: Option<String>,
                activity: DocumentActivity,
                source: DocumentSource,
@@ -2887,7 +2889,7 @@ impl DocumentMethods for Document {
 
     // https://dom.spec.whatwg.org/#dom-document-content_type
     fn ContentType(&self) -> DOMString {
-        self.content_type.clone()
+        DOMString::from(self.content_type.to_string())
     }
 
     // https://dom.spec.whatwg.org/#dom-document-doctype
@@ -2967,7 +2969,8 @@ impl DocumentMethods for Document {
             local_name.make_ascii_lowercase();
         }
 
-        let ns = if self.is_html_document || self.content_type == "application/xhtml+xml" {
+        let is_xhtml = self.content_type.0 == TopLevel::Application && self.content_type.1.as_str() == "xhtml+xml";
+        let ns = if self.is_html_document || is_xhtml {
             ns!(html)
         } else {
             ns!()