Prevent excessive processing of weak maps while marking.

src/heap.h

 // Copyright 2012 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 2693 matching lines @@
       MC_MARK,
       MC_SWEEP,
       MC_SWEEP_NEWSPACE,
       MC_EVACUATE_PAGES,
       MC_UPDATE_NEW_TO_NEW_POINTERS,
       MC_UPDATE_ROOT_TO_NEW_POINTERS,
       MC_UPDATE_OLD_TO_NEW_POINTERS,
       MC_UPDATE_POINTERS_TO_EVACUATED,
       MC_UPDATE_POINTERS_BETWEEN_EVACUATED,
       MC_UPDATE_MISC_POINTERS,
+      MC_WEAKMAP_PROCESS,
+      MC_WEAKMAP_CLEAR,
       MC_FLUSH_CODE,
       kNumberOfScopes
     };
 
     Scope(GCTracer* tracer, ScopeId scope)
         : tracer_(tracer),
         scope_(scope) {
       start_time_ = OS::TimeCurrentMillis();
     }
 
@@ skipping 314 matching lines @@
   DisallowHeapAllocation no_allocation;  // i.e. no gc allowed.
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_H_