List marker pseudo elements.

Source/core/core.gypi

 {
     'includes': [
         'core_generated.gypi',
     ],
     'variables': {
         # Files for which bindings (.cpp and .h files) will be generated
         'core_idl_files': [
             'animation/Animation.idl',
             'animation/AnimationEffect.idl',
             'animation/AnimationNode.idl',
@@ skipping 2215 matching lines @@
             'dom/LayoutTreeBuilder.cpp',
             'dom/LayoutTreeBuilder.h',
             'dom/LayoutTreeBuilderTraversal.cpp',
             'dom/LayoutTreeBuilderTraversal.h',
             'dom/LiveNodeList.cpp',
             'dom/LiveNodeList.h',
             'dom/LiveNodeListBase.cpp',
             'dom/LiveNodeListBase.h',
             'dom/MainThreadTaskRunner.cpp',
             'dom/MainThreadTaskRunner.h',
+            'dom/MarkerPseudoElement.h',
+            'dom/MarkerPseudoElement.cpp',
             'dom/MessageChannel.cpp',
             'dom/MessageChannel.h',
             'dom/MessagePort.cpp',
             'dom/Microtask.cpp',
             'dom/Microtask.h',
             'dom/MutationCallback.h',
             'dom/MutationObserver.cpp',
             'dom/MutationObserver.h',
             'dom/MutationObserverInterestGroup.cpp',
             'dom/MutationObserverInterestGroup.h',
@@ skipping 1582 matching lines @@
             'paint/LayerClipRecorderTest.cpp',
             'paint/LayoutObjectDrawingRecorderTest.cpp',
             'paint/TextPainterTest.cpp',
             'streams/ReadableStreamReaderTest.cpp',
             'streams/ReadableStreamTest.cpp',
             'testing/PrivateScriptTestTest.cpp',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }