Worklet: Introduce "pending tasks struct" concept defined in the Worklet spec

third_party/WebKit/Source/core/loader/WorkletScriptLoader.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef WorkletScriptLoader_h
 #define WorkletScriptLoader_h
 
 #include "core/CoreExport.h"
 #include "core/loader/resource/ScriptResource.h"
 #include "platform/loader/fetch/ResourceClient.h"
@@ skipping 36 matching lines @@
   void FetchScript(const String& script_url);
 
   // Cancels resource loading and synchronously calls
   // Client::notifyWorkletScriptLoadingFinished().
   void Cancel();
 
   // Returns true if a script was successfully loaded. This should be called
   // after Client::notifyWorkletScriptLoadingFinished() is called.
   bool WasScriptLoadSuccessful() const;
 
-  void set_request_id(int32_t request_id) { request_id_ = request_id; }
-  int32_t request_id() const { return request_id_; }
-
   DECLARE_TRACE();
 
  private:
   WorkletScriptLoader(ResourceFetcher*, Client*);
 
   // ResourceClient
   void NotifyFinished(Resource*) final;
   String DebugName() const final { return "WorkletLoader"; }
 
   Member<ResourceFetcher> fetcher_;
   Member<Client> client_;
 
-  // The client of this loader can freely use this field to identify a fetch
-  // request.
-  int32_t request_id_ = -1;
-
   bool was_script_load_successful_ = false;
   bool was_script_load_complete_ = false;
 };
 
 }  // namespace blink
 
 #endif  // WorkletScriptLoader_h