Worklet: Lazily create PaintWorkletGlobalScopes

third_party/WebKit/Source/modules/csspaint/PaintWorklet.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 PaintWorklet_h
 #define PaintWorklet_h
 
 #include "core/workers/MainThreadWorklet.h"
 #include "modules/ModulesExport.h"
 #include "modules/csspaint/PaintWorkletGlobalScopeProxy.h"
+#include "modules/csspaint/PaintWorkletPendingGeneratorRegistry.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
 class CSSPaintDefinition;
 class CSSPaintImageGeneratorImpl;
 
 // Manages a paint worklet:
 // https://drafts.css-houdini.org/css-paint-api/#dom-css-paintworklet
 class MODULES_EXPORT PaintWorklet final : public MainThreadWorklet {
   WTF_MAKE_NONCOPYABLE(PaintWorklet);
 
  public:
   static PaintWorklet* Create(LocalFrame*);
   ~PaintWorklet() override;
 
-  WorkletGlobalScopeProxy* GetWorkletGlobalScopeProxy() const final;
   CSSPaintDefinition* FindDefinition(const String& name);
   void AddPendingGenerator(const String& name, CSSPaintImageGeneratorImpl*);
 
   DECLARE_VIRTUAL_TRACE();
 
  private:
+  friend class PaintWorkletTest;
+
   explicit PaintWorklet(LocalFrame*);
 
-  // TODO(nhiroki): Make (Paint)WorkletGlobalScopeProxy GC-managed object.
-  std::unique_ptr<PaintWorkletGlobalScopeProxy> global_scope_proxy_;
+  // Implements MainThreadWorklet.
+  bool NeedsToCreateGlobalScope() final;
+  std::unique_ptr<WorkletGlobalScopeProxy> CreateGlobalScope() final;
+
+  // Used for keeping pending generators until the first PaintWorkletGlobalScope
+  // is created. Ownership of this registry is transferred to the global scope.
+  Member<PaintWorkletPendingGeneratorRegistry> pending_generator_registry_;
 };
 
 }  // namespace blink
 
 #endif  // PaintWorklet_h