Introduce IsGraphemeBreak function.

third_party/WebKit/Source/core/core.gypi

 {
     'includes': [
         'core_generated.gypi',
     ],
     'variables': {
         # Files for which bindings (.cpp and .h files) will be generated
         'core_idl_files': [
             'animation/KeyframeEffect.idl',
             'animation/EffectModel.idl',
             'animation/AnimationEffectReadOnly.idl',
@@ skipping 1578 matching lines @@
             'editing/spellcheck/SpellCheckRequester.cpp',
             'editing/spellcheck/SpellCheckRequester.h',
             'editing/spellcheck/SpellChecker.cpp',
             'editing/spellcheck/SpellChecker.h',
             'editing/spellcheck/TextCheckingHelper.cpp',
             'editing/spellcheck/TextCheckingHelper.h',
             'editing/state_machines/BackspaceStateMachine.cpp',
             'editing/state_machines/BackspaceStateMachine.h',
             'editing/state_machines/TextSegmentationMachineState.cpp',
             'editing/state_machines/TextSegmentationMachineState.h',
+            'editing/state_machines/StateMachineUtil.cpp',
+            'editing/state_machines/StateMachineUtil.h',
             'fetch/AccessControlStatus.h',
             'fetch/CSSStyleSheetResource.cpp',
             'fetch/CSSStyleSheetResource.h',
             'fetch/CachedMetadata.h',
             'fetch/CachedMetadataHandler.h',
             'fetch/ClientHintsPreferences.cpp',
             'fetch/ClientHintsPreferences.h',
             'fetch/CrossOriginAccessControl.cpp',
             'fetch/CrossOriginAccessControl.h',
             'fetch/DocumentResource.cpp',
@@ skipping 2350 matching lines @@
             'editing/markers/DocumentMarkerControllerTest.cpp',
             'editing/PositionTest.cpp',
             'editing/SelectionAdjusterTest.cpp',
             'editing/SurroundingTextTest.cpp',
             'editing/VisiblePositionTest.cpp',
             'editing/VisibleSelectionTest.cpp',
             'editing/VisibleUnitsTest.cpp',
             'editing/serializers/StyledMarkupSerializerTest.cpp',
             'editing/spellcheck/SpellCheckerTest.cpp',
             'editing/state_machines/BackspaceStateMachineTest.cpp',
+            'editing/state_machines/StateMachineUtilTest.cpp',
             'events/EventPathTest.cpp',
             'events/PointerEventFactoryTest.cpp',
             'fetch/CachingCorrectnessTest.cpp',
             'fetch/ClientHintsPreferencesTest.cpp',
             'fetch/FetchUtilsTest.cpp',
             'fetch/ImageResourceTest.cpp',
             'fetch/MemoryCacheTest.cpp',
             'fetch/MockResourceClients.cpp',
             'fetch/MultipartImageResourceParserTest.cpp',
             'fetch/RawResourceTest.cpp',
@@ skipping 102 matching lines @@
             'svg/SVGPathParserTest.cpp',
             'svg/UnsafeSVGAttributeSanitizationTest.cpp',
             'testing/PrivateScriptTestTest.cpp',
             'timing/MemoryInfoTest.cpp',
             'workers/WorkerThreadTest.cpp',
             'workers/WorkerThreadTestHelper.h',
             'xml/parser/SharedBufferReaderTest.cpp',
         ],
     }
 }