Remove MemoryUsageSupport

Source/platform/blink_platform.gypi

 {
   'variables': {
     'platform_files': [
       'CalculationValue.cpp',
       'CalculationValue.h',
       'Clock.cpp',
       'Clock.h',
       'ContentType.cpp',
       'ContentType.h',
       'CrossThreadCopier.cpp',
@@ skipping 23 matching lines @@
       'LengthBox.cpp',
       'LengthBox.h',
       'LengthFunctions.cpp',
       'LengthFunctions.h',
       'LengthPoint.h',
       'LengthSize.h',
       'LinkHash.cpp',
       'LinkHash.h',
       'Logging.cpp',
       'Logging.h',
+      'MemoryUsageSupport.cpp',
+      'MemoryUsageSupport.h',
       'NotImplemented.cpp',
       'NotImplemented.h',
       'PODArena.h',
       'PODFreeListArena.h',
       'PODInterval.h',
       'PODIntervalTree.h',
       'PODRedBlackTree.h',
       'Partitions.cpp',
       'Partitions.h',
       'PasteMode.h',
@@ skipping 303 matching lines @@
       'geometry/RegionTest.cpp',
       'geometry/RoundedRectTest.cpp',
       'graphics/ThreadSafeDataTransportTest.cpp',
       'testing/ArenaTestHelpers.h',
       'testing/TreeTestHelpers.cpp',
       'testing/TreeTestHelpers.h',
       'text/DateTimeFormatTest.cpp',
     ],
   },
 }