Implement PaintWorkletGlobalScope#registerPaint() for the CSS Paint API

third_party/WebKit/Source/modules/modules.gypi

 {
   'includes': [
     '../core/core_generated.gypi',
     'modules_generated.gypi',
   ],
   'variables': {
     # Experimental hooks for embedder to provide extra IDL and source files.
     #
     # Note: this is not a supported API. If you rely on this, you will be broken
     # from time to time as the code generator changes in backward incompatible
@@ skipping 909 matching lines @@
       'crypto/CryptoResultImpl.cpp',
       'crypto/CryptoResultImpl.h',
       'crypto/DOMWindowCrypto.cpp',
       'crypto/DOMWindowCrypto.h',
       'crypto/NormalizeAlgorithm.cpp',
       'crypto/NormalizeAlgorithm.h',
       'crypto/SubtleCrypto.cpp',
       'crypto/SubtleCrypto.h',
       'crypto/WorkerGlobalScopeCrypto.cpp',
       'crypto/WorkerGlobalScopeCrypto.h',
+      'csspaint/CSSPaintDefinition.cpp',
+      'csspaint/CSSPaintDefinition.h',
       'csspaint/PaintRenderingContext2D.cpp',
       'csspaint/PaintRenderingContext2D.h',
       'csspaint/PaintWorklet.cpp',
       'csspaint/PaintWorklet.h',
       'csspaint/PaintWorkletGlobalScope.cpp',
       'csspaint/PaintWorkletGlobalScope.h',
       'csspaint/WindowPaintWorklet.cpp',
       'csspaint/WindowPaintWorklet.h',
       'device_light/DeviceLightController.cpp',
       'device_light/DeviceLightController.h',
@@ skipping 1063 matching lines @@
       'webaudio/AudioBasicProcessorHandlerTest.cpp',
       'webaudio/ConvolverNodeTest.cpp',
       'webaudio/DynamicsCompressorNodeTest.cpp',
       'webaudio/ScriptProcessorNodeTest.cpp',
       'webaudio/StereoPannerNodeTest.cpp',
       'websockets/DOMWebSocketTest.cpp',
       'websockets/DocumentWebSocketChannelTest.cpp',
     ],
   },
 }