Encapsulate element handling into a class keyed on ElementsKind

tools/gyp/v8.gyp

 # Copyright 2011 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 470 matching lines @@
             '../../src/deoptimizer.cc',
             '../../src/deoptimizer.h',
             '../../src/disasm.h',
             '../../src/disassembler.cc',
             '../../src/disassembler.h',
             '../../src/dtoa.cc',
             '../../src/dtoa.h',
             '../../src/diy-fp.cc',
             '../../src/diy-fp.h',
             '../../src/double.h',
+            '../../src/elements.cc',
+            '../../src/elements.h',
             '../../src/execution.cc',
             '../../src/execution.h',
             '../../src/factory.cc',
             '../../src/factory.h',
             '../../src/fast-dtoa.cc',
             '../../src/fast-dtoa.h',
             '../../src/flag-definitions.h',
             '../../src/fixed-dtoa.cc',
             '../../src/fixed-dtoa.h',
             '../../src/flags.cc',
@@ skipping 503 matching lines @@
           'type': 'none',
           'toolsets': ['host'],
           'dependencies': [
             'v8'
           ],
         },
       ],
     }],
   ],
 }