[DONT COMMIT] Worklet: Implement "addModule()" algorithm for main thread worklets

third_party/WebKit/Source/modules/csspaint/BUILD.gn

 # 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.
 
 import("//third_party/WebKit/Source/modules/modules.gni")
 
 blink_modules_sources("csspaint") {
   sources = [
     "CSSPaintDefinition.cpp",
     "CSSPaintDefinition.h",
     "CSSPaintImageGeneratorImpl.cpp",
     "CSSPaintImageGeneratorImpl.h",
     "PaintRenderingContext2D.cpp",
     "PaintRenderingContext2D.h",
     "PaintSize.h",
     "PaintWorklet.cpp",
     "PaintWorklet.h",
     "PaintWorkletGlobalScope.cpp",
     "PaintWorkletGlobalScope.h",
+    "PaintWorkletGlobalScopeProxy.cpp",
+    "PaintWorkletGlobalScopeProxy.h",
     "WindowPaintWorklet.cpp",
     "WindowPaintWorklet.h",
   ]
 }