Worklet: Introduce PaintWorkletGlobalScopeProxy

third_party/WebKit/Source/core/workers/WorkletGlobalScopeProxy.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 WorkletGlobalScopeProxy_h
 #define WorkletGlobalScopeProxy_h
 
 #include "core/CoreExport.h"
 #include "platform/weborigin/KURL.h"
 
 namespace blink {
 
 class ScriptSourceCode;
 class WorkletPendingTasks;
 
-// A proxy to talk to the worklet global scope. The global scope may exist in
-// the main thread or on a different thread.
+// Abstracts communication from (Main/Threaded)Worklet on the main thread to
+// (Main/Threaded)WorkletGlobalScope so that Worklet class doesn't have to care
+// about the thread WorkletGlobalScope runs on.
 class CORE_EXPORT WorkletGlobalScopeProxy {
  public:
   virtual ~WorkletGlobalScopeProxy() {}
 
   // Runs the "fetch and invoke a worklet script" algorithm:
   // https://drafts.css-houdini.org/worklets/#fetch-and-invoke-a-worklet-script
   virtual void FetchAndInvokeScript(const KURL& module_url_record,
                                     WorkletPendingTasks*) {}
 
   // Evaluates the given script source code. This should be called only for
   // threaded worklets that still use classic script loading.
   virtual void EvaluateScript(const ScriptSourceCode&) = 0;
 
   // Terminates the worklet global scope from the main thread.
   virtual void TerminateWorkletGlobalScope() = 0;
 };
 
 }  // namespace blink
 
 #endif  // WorkletGlobalScopeProxy_h