Track JS allocations as they arrive with no affection on performance when tracking is switched off

test/cctest/cctest.cc

 // Copyright 2008 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 156 matching lines @@
     }
   }
   if (print_run_count && tests_run != 1)
     printf("Ran %i tests.\n", tests_run);
   v8::V8::Dispose();
   return 0;
 }
 
 RegisterThreadedTest *RegisterThreadedTest::first_ = NULL;
 int RegisterThreadedTest::count_ = 0;
+
+void RunAndTrackAllocations(void (*test)()) {
+  LocalContext env;
+  HeapObjectsTracker tracker;
+  (*test)();
+}