[heap] Implement simple concurrent marking deque.

test/unittests/unittests.gyp

 # Copyright 2014 the V8 project authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # The sources are kept automatically in sync with BUILD.gn.
 
 {
   'variables': {
     'v8_code': 1,
     'unittests_sources': [  ### gcmole(all) ###
@@ skipping 79 matching lines @@
       'compiler/value-numbering-reducer-unittest.cc',
       'compiler/zone-stats-unittest.cc',
       'compiler-dispatcher/compiler-dispatcher-job-unittest.cc',
       'compiler-dispatcher/compiler-dispatcher-tracer-unittest.cc',
       'compiler-dispatcher/compiler-dispatcher-unittest.cc',
       'compiler-dispatcher/optimizing-compile-dispatcher-unittest.cc',
       'counters-unittest.cc',
       'eh-frame-iterator-unittest.cc',
       'eh-frame-writer-unittest.cc',
       'heap/bitmap-unittest.cc',
+      'heap/concurrent-marking-deque-unittest.cc',
       'heap/embedder-tracing-unittest.cc',
       'heap/gc-idle-time-handler-unittest.cc',
       'heap/gc-tracer-unittest.cc',
       'heap/marking-unittest.cc',
       'heap/memory-reducer-unittest.cc',
       'heap/heap-unittest.cc',
       'heap/scavenge-job-unittest.cc',
       'heap/slot-set-unittest.cc',
       'heap/spaces-unittest.cc',
       'heap/unmapper-unittest.cc',
@@ skipping 165 matching lines @@
             '../../gypfiles/isolate.gypi',
           ],
           'sources': [
             'unittests.isolate',
           ],
         },
       ],
     }],
   ],
 }