Add terminateServiceWorker method for layout tests - blink side

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 1001 matching lines @@
       'websockets/WebSocketChannelClient.h',
       'websockets/WebSocketFrame.cpp',
       'websockets/WebSocketFrame.h',
       'websockets/WorkerThreadableWebSocketChannel.cpp',
       'websockets/WorkerThreadableWebSocketChannel.h',
     ],
     # 'partial interface' or target (right side of) 'implements'
     'modules_testing_dependency_idl_files' : [
       'geolocation/testing/InternalsGeolocation.idl',
       'navigatorcontentutils/testing/InternalsNavigatorContentUtils.idl',
+      'serviceworkers/testing/InternalsServiceWorker.idl',
       'speech/testing/InternalsSpeechSynthesis.idl',
       'vibration/testing/InternalsVibration.idl',
     ],
     'modules_testing_files': [
       'geolocation/testing/GeolocationClientMock.cpp',
       'geolocation/testing/GeolocationClientMock.h',
       'geolocation/testing/InternalsGeolocation.cpp',
       'geolocation/testing/InternalsGeolocation.h',
       'navigatorcontentutils/testing/InternalsNavigatorContentUtils.cpp',
       'navigatorcontentutils/testing/InternalsNavigatorContentUtils.h',
       'navigatorcontentutils/testing/NavigatorContentUtilsClientMock.cpp',
       'navigatorcontentutils/testing/NavigatorContentUtilsClientMock.h',
+      'serviceworkers/testing/InternalsServiceWorker.cpp',
+      'serviceworkers/testing/InternalsServiceWorker.h',
       'speech/testing/InternalsSpeechSynthesis.cpp',
       'speech/testing/InternalsSpeechSynthesis.h',
       'speech/testing/PlatformSpeechSynthesizerMock.cpp',
       'speech/testing/PlatformSpeechSynthesizerMock.h',
       'vibration/testing/InternalsVibration.cpp',
       'vibration/testing/InternalsVibration.h',
     ],
     'modules_unittest_files': [
       'filesystem/DOMFileSystemBaseTest.cpp',
       'indexeddb/IDBKeyPathTest.cpp',
       'indexeddb/IDBRequestTest.cpp',
       'indexeddb/IDBTransactionTest.cpp',
       'serviceworkers/CacheTest.cpp',
       'serviceworkers/FetchResponseDataTest.cpp',
       'serviceworkers/RequestTest.cpp',
       'serviceworkers/ResponseTest.cpp',
       'serviceworkers/ServiceWorkerContainerTest.cpp',
       'websockets/DOMWebSocketTest.cpp',
       'websockets/NewWebSocketChannelImplTest.cpp',
     ],
   },
 }