Move remaining core/platform/mac files to platform/mac

Source/platform/blink_platform.gypi

 {
   'variables': {
     'platform_files': [
       'AsyncFileSystemCallbacks.h',
       'CalculationValue.cpp',
       'CalculationValue.h',
       'CheckedInt.h',
       'Clock.cpp',
       'Clock.h',
       'ColorChooser.cpp',
@@ skipping 667 matching lines @@
       'mac/ColorMac.h',
       'mac/ColorMac.mm',
       'mac/LocalCurrentGraphicsContext.h',
       'mac/LocalCurrentGraphicsContext.mm',
       'mac/NSScrollerImpDetails.h',
       'mac/NSScrollerImpDetails.mm',
       'mac/ScrollAnimatorMac.h',
       'mac/ScrollAnimatorMac.mm',
       'mac/ScrollElasticityController.h',
       'mac/ScrollElasticityController.mm',
+      'mac/ThemeMac.h',
+      'mac/ThemeMac.mm',
       'mac/WebCoreNSCellExtras.h',
       'mac/WebFontCache.h',
       'mac/WebFontCache.mm',
       'mediastream/MediaConstraints.cpp',
       'mediastream/MediaConstraints.h',
       'mediastream/MediaStreamComponent.cpp',
       'mediastream/MediaStreamComponent.h',
       'mediastream/MediaStreamSource.cpp',
       'mediastream/MediaStreamSource.h',
       'mediastream/RTCConfiguration.h',
@@ skipping 208 matching lines @@
       'text/BidiResolverTest.cpp',
       'text/DateTimeFormatTest.cpp',
       'text/UnicodeUtilitiesTest.cpp',
       'weborigin/DatabaseIdentifierTest.cpp',
       'weborigin/KURLTest.cpp',
       'weborigin/OriginAccessEntryTest.cpp',
       'weborigin/SecurityOriginTest.cpp',
     ],
   },
 }