Include WebViewId into EmbedderMsg variants where possible (#35211)

`EmbedderMsg` was previously paired with an implicit
`Option<WebViewId>`, even though almost all variants were either always
`Some` or always `None`, depending on whether there was a `WebView
involved.

This patch adds the `WebViewId` to as many `EmbedderMsg` variants as
possible, so we can call their associated `WebView` delegate methods
without needing to check and unwrap the `Option`. In many cases, this
required more changes to plumb through the `WebViewId`.

Notably, all `Request`s now explicitly need a `WebView` or not, in order
to ensure that it is passed when appropriate.

Signed-off-by: Delan Azabani <dazabani@igalia.com>
Co-authored-by: Martin Robinson <mrobinson@igalia.com>

components/net/fetch/methods.rs

@@ -195,18 +195,6 @@ pub fn should_request_be_blocked_by_csp(
         .unwrap_or(csp::CheckResult::Allowed)
 }
 
-pub fn maybe_intercept_request(
-    request: &mut Request,
-    context: &FetchContext,
-    response: &mut Option<Response>,
-) {
-    context
-        .request_intercepter
-        .lock()
-        .unwrap()
-        .intercept_request(request, response, context);
-}
-
 /// [Main fetch](https://fetch.spec.whatwg.org/#concept-main-fetch)
 pub async fn main_fetch(
     fetch_params: &mut FetchParams,
@@ -314,7 +302,11 @@ pub async fn main_fetch(
     let current_scheme = current_url.scheme();
 
     // Intercept the request and maybe override the response.
-    maybe_intercept_request(request, context, &mut response);
+    context
+        .request_intercepter
+        .lock()
+        .unwrap()
+        .intercept_request(request, &mut response, context);
 
     let mut response = match response {
         Some(res) => res,