Worklet: Lazily create PaintWorkletGlobalScopes

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

Index: third_party/WebKit/Source/core/workers/MainThreadWorklet.h
diff --git a/third_party/WebKit/Source/core/workers/MainThreadWorklet.h b/third_party/WebKit/Source/core/workers/MainThreadWorklet.h
index 998ab298423c43e06d00262cea343ab3d212918f..1b6fb78a858b0ce671c09a507c3a25129c80f02b 100644
--- a/third_party/WebKit/Source/core/workers/MainThreadWorklet.h
+++ b/third_party/WebKit/Source/core/workers/MainThreadWorklet.h
@@ -9,12 +9,14 @@
 
 #include "bindings/core/v8/ScriptPromise.h"
 #include "core/CoreExport.h"
+#include "core/workers/WorkletGlobalScopeManager.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
 class LocalFrame;
 class ScriptPromiseResolver;
+class WorkletGlobalScopeProxy;
 
 // A MainThreadWorklet is a worklet that runs only on the main thread.
 // TODO(nhiroki): This is a temporary class to support module loading for main
@@ -30,6 +32,10 @@ class CORE_EXPORT MainThreadWorklet : public Worklet {
   // ContextLifecycleObserver
   void ContextDestroyed(ExecutionContext*) final;
 
+  WorkletGlobalScopeManager& GetGlobalScopeManager() {
+    return *global_scope_manager_;
+  }
+
   DECLARE_VIRTUAL_TRACE();
 
  protected:
@@ -40,6 +46,14 @@ class CORE_EXPORT MainThreadWorklet : public Worklet {
   void FetchAndInvokeScript(const KURL& module_url_record,
                             const WorkletOptions&,
                             ScriptPromiseResolver*) override;
+
+  // Returns true if there are no global scopes or additional global scopes are
+  // necessary. CreateGlobalScope() will be called in that case. Each worklet
+  // can define how to pool global scopes here.
+  virtual bool NeedsToCreateGlobalScope() = 0;
+  virtual std::unique_ptr<WorkletGlobalScopeProxy> CreateGlobalScope() = 0;
+
+  Member<WorkletGlobalScopeManager> global_scope_manager_;
 };
 
 }  // namespace blink