Implement HTMLCanvasElement's transferControlToOffscreen

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 1952 matching lines @@
       'speech/testing/PlatformSpeechSynthesizerMock.cpp',
       'speech/testing/PlatformSpeechSynthesizerMock.h',
       'vibration/testing/InternalsVibration.cpp',
       'vibration/testing/InternalsVibration.h',
       'webaudio/testing/InternalsWebAudio.h',
       'webaudio/testing/InternalsWebAudio.cpp',
     ],
     'modules_unittest_files': [
       'accessibility/AXObjectTest.cpp',
       'cachestorage/CacheTest.cpp',
+      'canvas/HTMLCanvasElementModuleTest.cpp',
       'canvas2d/CanvasRenderingContext2DAPITest.cpp',
       'canvas2d/CanvasRenderingContext2DTest.cpp',
       'compositorworker/CompositorWorkerThreadTest.cpp',
       'csspaint/PaintRenderingContext2DTest.cpp',
       'fetch/BodyStreamBufferTest.cpp',
       'fetch/CompositeDataConsumerHandleTest.cpp',
       'fetch/DataConsumerHandleTestUtil.cpp',
       'fetch/DataConsumerHandleTestUtil.h',
       'fetch/DataConsumerHandleUtilTest.cpp',
       'fetch/DataConsumerTeeTest.cpp',
@@ skipping 21 matching lines @@
       'webaudio/AudioBasicProcessorHandlerTest.cpp',
       'webaudio/ConvolverNodeTest.cpp',
       'webaudio/DynamicsCompressorNodeTest.cpp',
       'webaudio/ScriptProcessorNodeTest.cpp',
       'webaudio/StereoPannerNodeTest.cpp',
       'websockets/DOMWebSocketTest.cpp',
       'websockets/DocumentWebSocketChannelTest.cpp',
     ],
   },
 }