Fixes for HTTP header compliance. (#32024)

- Fix 400 errors from nginx in response to Servo requests by implementing conformant albeit non-normative removal of whitespace from `Accept` and `Accept-Language` HTTP headers. (To match behaviour of Firefox, Safari, and Chrome) https://datatracker.ietf.org/doc/html/rfc7231#section-5.3.2
- Provide `Host` header as REQUIRED by HTTP protocol https://www.rfc-editor.org/rfc/rfc9110#field.host
- Update tests.

components/net/http_loader.rs

@@ -1225,7 +1225,20 @@ async fn http_network_or_cache_fetch(
 
     // Step 5.16
     let current_url = http_request.current_url();
-    http_request.headers.remove(header::HOST);
+    if !http_request.headers.contains_key(header::HOST) {
+        let host = if current_url.port().is_none() {
+            current_url.host_str().unwrap().to_string()
+        } else {
+            format!(
+                "{}:{}",
+                current_url.host_str().unwrap(),
+                current_url.port().unwrap()
+            )
+        };
+        http_request.headers.typed_insert(headers::Host::from(
+            host.parse::<http::uri::Authority>().unwrap(),
+        ));
+    }
 
     // unlike http_loader, we should not set the accept header
     // here, according to the fetch spec

components/net/tests/fetch.rs

@@ -1350,11 +1350,6 @@ fn test_fetch_with_devtools() {
     //Creating default headers for request
     let mut headers = HeaderMap::new();
 
-    headers.insert(
-        header::ACCEPT_ENCODING,
-        HeaderValue::from_static("gzip, deflate, br"),
-    );
-
     headers.insert(header::ACCEPT, HeaderValue::from_static("*/*"));
 
     headers.insert(
@@ -1364,6 +1359,20 @@ fn test_fetch_with_devtools() {
 
     headers.typed_insert::<UserAgent>(DEFAULT_USER_AGENT.parse().unwrap());
 
+    let host = if url.port().is_none() {
+        url.host_str().unwrap().to_string()
+    } else {
+        format!("{}:{}", url.host_str().unwrap(), url.port().unwrap())
+    };
+    headers.typed_insert(headers::Host::from(
+        host.parse::<http::uri::Authority>().unwrap(),
+    ));
+
+    headers.insert(
+        header::ACCEPT_ENCODING,
+        HeaderValue::from_static("gzip, deflate, br"),
+    );
+
     let httprequest = DevtoolsHttpRequest {
         url: url,
         method: Method::GET,

components/net/tests/http_loader.rs

@@ -136,9 +136,7 @@ fn test_check_default_headers_loaded_in_every_request() {
 
     headers.insert(
         header::ACCEPT,
-        HeaderValue::from_static(
+        HeaderValue::from_static("text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"),
-            "text/html, application/xhtml+xml, application/xml; q=0.9, */*; q=0.8",
-        ),
     );
 
     headers.insert(
@@ -268,16 +266,11 @@ fn test_request_and_response_data_with_network_messages() {
     //Creating default headers for request
     let mut headers = HeaderMap::new();
 
-    headers.insert(
+    headers.insert(header::HOST, HeaderValue::from_static("bar.foo"));
-        header::ACCEPT_ENCODING,
-        HeaderValue::from_static("gzip, deflate, br"),
-    );
 
     headers.insert(
         header::ACCEPT,
-        HeaderValue::from_static(
+        HeaderValue::from_static("text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"),
-            "text/html, application/xhtml+xml, application/xml; q=0.9, */*; q=0.8",
-        ),
     );
 
     headers.insert(
@@ -287,6 +280,11 @@ fn test_request_and_response_data_with_network_messages() {
 
     headers.typed_insert::<UserAgent>(crate::DEFAULT_USER_AGENT.parse().unwrap());
 
+    headers.insert(
+        header::ACCEPT_ENCODING,
+        HeaderValue::from_static("gzip, deflate, br"),
+    );
+
     let httprequest = DevtoolsHttpRequest {
         url: url,
         method: Method::GET,