Bug 1618292 - Make ScriptLoadRequest derive and use PreloaderBase to support new preload as speculative load feature, r=smaug

Depends on D67483

Differential Revision: https://phabricator.services.mozilla.com/D67481

dom/script/ScriptLoadRequest.h

@@ -12,12 +12,14 @@
 #include "mozilla/dom/SRIMetadata.h"
 #include "mozilla/LinkedList.h"
 #include "mozilla/Maybe.h"
+#include "mozilla/PreloaderBase.h"
 #include "mozilla/Utf8.h"  // mozilla::Utf8Unit
 #include "mozilla/Variant.h"
 #include "mozilla/Vector.h"
 #include "nsCOMPtr.h"
 #include "nsCycleCollectionParticipant.h"
 #include "nsIScriptElement.h"
+#include "ScriptKind.h"
 
 class nsICacheInfoChannel;
 
@@ -27,8 +29,6 @@ namespace dom {
 class ModuleLoadRequest;
 class ScriptLoadRequestList;
 
-enum class ScriptKind { eClassic, eModule };
-
 /*
  * Some options used when fetching script resources. This only loosely
  * corresponds to HTML's "script fetch options".
@@ -61,7 +61,7 @@ class ScriptFetchOptions {
  */
 
 class ScriptLoadRequest
-    : public nsISupports,
+    : public PreloaderBase,
       private mozilla::LinkedListElement<ScriptLoadRequest> {
   typedef LinkedListElement<ScriptLoadRequest> super;
 
@@ -80,6 +80,10 @@ class ScriptLoadRequest
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(ScriptLoadRequest)
 
+  // PreloaderBase
+  static void PrioritizeAsPreload(nsIChannel* aChannel);
+  virtual void PrioritizeAsPreload() override;
+
   bool IsModuleRequest() const { return mKind == ScriptKind::eModule; }
 
   ModuleLoadRequest* AsModuleRequest();