Worklet: Lazily create PaintWorkletGlobalScopes

third_party/WebKit/Source/core/workers/ThreadedWorklet.h

 // Copyright 2017 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 ThreadedWorklet_h
 #define ThreadedWorklet_h
 
 #include "core/workers/Worklet.h"
 
 #include "bindings/core/v8/ScriptPromiseResolver.h"
 #include "core/CoreExport.h"
 #include "core/loader/WorkletScriptLoader.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
 class LocalFrame;
+class WorkletGlobalScopeProxy;
 
 // A ThreadedWorklet is a worklet that runs off the main thread.
 // TODO(nhiroki): This is a temporary class to keep classic script loading for
 // threaded worklets while module loading is being implemented for main thread
 // worklets. This and MainThreadWorklet will be merged into the base Worklet
 // class once threaded worklets are also ready to use module loading.
 class CORE_EXPORT ThreadedWorklet : public Worklet,
                                     public WorkletScriptLoader::Client {
   USING_GARBAGE_COLLECTED_MIXIN(ThreadedWorklet);
   WTF_MAKE_NONCOPYABLE(ThreadedWorklet);
 
  public:
   virtual ~ThreadedWorklet() = default;
 
   // WorkletScriptLoader::Client
   void NotifyWorkletScriptLoadingFinished(WorkletScriptLoader*,
                                           const ScriptSourceCode&) final;
 
   // ContextLifecycleObserver
   void ContextDestroyed(ExecutionContext*) final;
 
+  // Returns a proxy to WorkletGlobalScope on the context thread.
+  virtual WorkletGlobalScopeProxy* GetWorkletGlobalScopeProxy() const = 0;
+
   DECLARE_VIRTUAL_TRACE();
 
  protected:
   explicit ThreadedWorklet(LocalFrame*);
 
  private:
   // Worklet
   void FetchAndInvokeScript(const KURL& module_url_record,
                             const WorkletOptions&,
                             ScriptPromiseResolver*) override;
 
   // Called when addModule() is called for the first time.
   virtual void Initialize() = 0;
   virtual bool IsInitialized() const = 0;
 
   Member<LocalFrame> frame_;
 
   HeapHashMap<Member<WorkletScriptLoader>, Member<ScriptPromiseResolver>>
       loader_to_resolver_map_;
 };
 
 }  // namespace blink
 
 #endif  // ThreadedWorklet_h