compositor-worker: Introduce CompositorWorker.

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
     # ways.
     'extra_blink_module_idl_files': [],
     'extra_blink_module_files': [],
     # Files for which bindings (.cpp and .h files) will be generated
     'modules_idl_files': [
       '<@(extra_blink_module_idl_files)',
       'app_banner/BeforeInstallPromptEvent.idl',
       'battery/BatteryManager.idl',
       'bluetooth/Bluetooth.idl',
       'bluetooth/BluetoothDevice.idl',
       'bluetooth/BluetoothDiscovery.idl',
+      'compositorworker/CompositorWorker.idl',
       'credentialmanager/Credential.idl',
       'credentialmanager/CredentialsContainer.idl',
       'credentialmanager/FederatedCredential.idl',
       'credentialmanager/LocalCredential.idl',
       'crypto/Crypto.idl',
       'crypto/CryptoKey.idl',
       'crypto/SubtleCrypto.idl',
       'device_light/DeviceLightEvent.idl',
       'device_orientation/DeviceAcceleration.idl',
       'device_orientation/DeviceMotionEvent.idl',
@@ skipping 497 matching lines @@
       'beacon/NavigatorBeacon.h',
       'bluetooth/Bluetooth.h',
       'bluetooth/BluetoothDevice.cpp',
       'bluetooth/BluetoothDevice.h',
       'bluetooth/BluetoothDiscovery.cpp',
       'bluetooth/BluetoothDiscovery.h',
       'bluetooth/BluetoothError.cpp',
       'bluetooth/BluetoothError.h',
       'bluetooth/NavigatorBluetooth.cpp',
       'bluetooth/NavigatorBluetooth.h',
+      'compositorworker/CompositorWorker.cpp',
+      'compositorworker/CompositorWorker.h',
+      'compositorworker/CompositorWorkerMessagingProxy.cpp',
+      'compositorworker/CompositorWorkerMessagingProxy.h',
+      'compositorworker/CompositorWorkerThread.cpp',
+      'compositorworker/CompositorWorkerThread.h',
       'credentialmanager/Credential.cpp',
       'credentialmanager/Credential.h',
       'credentialmanager/CredentialManagerClient.cpp',
       'credentialmanager/CredentialManagerClient.h',
       'credentialmanager/CredentialsContainer.cpp',
       'credentialmanager/CredentialsContainer.h',
       'credentialmanager/FederatedCredential.cpp',
       'credentialmanager/FederatedCredential.h',
       'credentialmanager/LocalCredential.cpp',
       'credentialmanager/LocalCredential.h',
@@ skipping 780 matching lines @@
       'indexeddb/IDBKeyPathTest.cpp',
       'indexeddb/IDBRequestTest.cpp',
       'indexeddb/IDBTransactionTest.cpp',
       'serviceworkers/CacheTest.cpp',
       'serviceworkers/ServiceWorkerContainerTest.cpp',
       'websockets/DOMWebSocketTest.cpp',
       'websockets/DocumentWebSocketChannelTest.cpp',
     ],
   },
 }