Bug 1839316: part 4) Add RequestPriority to ScriptFetchOptions and ScriptLoadRequest. r=smaug

The request priority isn't propagated from `ScriptFetchOptions`, so
setting it has no effect for end-users. That will be implemented in a
following part.

Differential Revision: https://phabricator.services.mozilla.com/D183483

js/loader/ScriptLoadRequest.cpp

@@ -37,11 +37,13 @@ NS_IMPL_CYCLE_COLLECTION(ScriptFetchOptions, mTriggeringPrincipal, mElement)
 
 ScriptFetchOptions::ScriptFetchOptions(
     mozilla::CORSMode aCORSMode, mozilla::dom::ReferrerPolicy aReferrerPolicy,
-    const nsAString& aNonce, const ParserMetadata aParserMetadata,
-    nsIPrincipal* aTriggeringPrincipal, mozilla::dom::Element* aElement)
+    const nsAString& aNonce, mozilla::dom::RequestPriority aFetchPriority,
+    const ParserMetadata aParserMetadata, nsIPrincipal* aTriggeringPrincipal,
+    mozilla::dom::Element* aElement)
     : mCORSMode(aCORSMode),
       mReferrerPolicy(aReferrerPolicy),
       mNonce(aNonce),
+      mFetchPriority(aFetchPriority),
       mParserMetadata(aParserMetadata),
       mTriggeringPrincipal(aTriggeringPrincipal),
       mElement(aElement) {}

js/loader/ScriptLoadRequest.h

@@ -37,6 +37,7 @@ namespace mozilla::dom {
 class ScriptLoadContext;
 class WorkerLoadContext;
 class WorkletLoadContext;
+enum class RequestPriority : uint8_t;
 
 }  // namespace mozilla::dom
 
@@ -88,6 +89,7 @@ class ScriptFetchOptions {
   ScriptFetchOptions(mozilla::CORSMode aCORSMode,
                      enum mozilla::dom::ReferrerPolicy aReferrerPolicy,
                      const nsAString& aNonce,
+                     mozilla::dom::RequestPriority aFetchPriority,
                      const ParserMetadata aParserMetadata,
                      nsIPrincipal* aTriggeringPrincipal,
                      mozilla::dom::Element* aElement = nullptr);
@@ -111,6 +113,11 @@ class ScriptFetchOptions {
    */
   const nsString mNonce;
 
+  /*
+   * <https://html.spec.whatwg.org/multipage/webappapis.html#script-fetch-options>.
+   */
+  const mozilla::dom::RequestPriority mFetchPriority;
+
   /*
    * The parser metadata used for the initial fetch and for fetching any
    * imported modules
@@ -288,6 +295,10 @@ class ScriptLoadRequest
                          : ScriptText<Utf8Unit>().clearAndFree();
   }
 
+  mozilla::dom::RequestPriority FetchPriority() const {
+    return mFetchOptions->mFetchPriority;
+  }
+
   enum mozilla::dom::ReferrerPolicy ReferrerPolicy() const {
     return mFetchOptions->mReferrerPolicy;
   }