Add rendering context and rendering 2D context to OffscreenCanvas

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 14 matching lines @@
       'bluetooth/BluetoothCharacteristicProperties.idl',
       'bluetooth/BluetoothRemoteGATTCharacteristic.idl',
       'bluetooth/BluetoothRemoteGATTServer.idl',
       'bluetooth/BluetoothRemoteGATTService.idl',
       'bluetooth/BluetoothUUID.idl',
       'cachestorage/Cache.idl',
       'cachestorage/CacheStorage.idl',
       'canvas2d/CanvasGradient.idl',
       'canvas2d/CanvasPattern.idl',
       'canvas2d/CanvasRenderingContext2D.idl',
+      'canvas2d/OffscreenCanvasRenderingContext2D.idl',
       'canvas2d/Path2D.idl',
       'compositorworker/CompositorWorker.idl',
       'compositorworker/CompositorWorkerGlobalScope.idl',
       'credentialmanager/Credential.idl',
       'credentialmanager/CredentialsContainer.idl',
       'credentialmanager/FederatedCredential.idl',
       'credentialmanager/PasswordCredential.idl',
       'crypto/Crypto.idl',
       'crypto/CryptoKey.idl',
       'crypto/SubtleCrypto.idl',
@@ skipping 800 matching lines @@
       'canvas2d/ClipList.cpp',
       'canvas2d/ClipList.h',
       'canvas2d/ContextAttributeHelpers.cpp',
       'canvas2d/ContextAttributeHelpers.h',
       'canvas2d/EventHitRegion.cpp',
       'canvas2d/EventHitRegion.h',
       'canvas2d/HitRegion.cpp',
       'canvas2d/HitRegion.h',
       'canvas2d/MouseEventHitRegion.cpp',
       'canvas2d/MouseEventHitRegion.h',
+      'canvas2d/OffscreenCanvasRenderingContext2D.cpp',
+      'canvas2d/OffscreenCanvasRenderingContext2D.h',
+      'canvas2d/OffscreenCanvasRenderingContext.h',
       'canvas2d/Path2D.h',
       'canvas2d/TouchHitRegion.cpp',
       'canvas2d/TouchHitRegion.h',
       'compositorworker/CompositorWorker.cpp',
       'compositorworker/CompositorWorker.h',
       'compositorworker/CompositorWorkerGlobalScope.cpp',
       'compositorworker/CompositorWorkerGlobalScope.h',
       'compositorworker/CompositorWorkerMessagingProxy.cpp',
       'compositorworker/CompositorWorkerMessagingProxy.h',
       'compositorworker/CompositorWorkerThread.cpp',
@@ skipping 1067 matching lines @@
       'webaudio/AudioBasicProcessorHandlerTest.cpp',
       'webaudio/ConvolverNodeTest.cpp',
       'webaudio/DynamicsCompressorNodeTest.cpp',
       'webaudio/ScriptProcessorNodeTest.cpp',
       'webaudio/StereoPannerNodeTest.cpp',
       'websockets/DOMWebSocketTest.cpp',
       'websockets/DocumentWebSocketChannelTest.cpp',
     ],
   },
 }