Add experimental support for tracing the state of the VM heap to a file

src/mark-compact.cc

 // 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 3541 matching lines @@
   }
 
   // Handle the free space at the end of the page.
   if (block_address - free_start > 32 * kPointerSize) {
     free_start = DigestFreeStart(free_start, free_start_cell);
     freed_bytes += space->Free(free_start,
                                static_cast<int>(block_address - free_start));
   }
 
   p->ResetLiveBytes();
+  p->heap()->UpdateVisualizers(p);
   return freed_bytes;
 }
 
 
 void MarkCompactCollector::SweepSpace(PagedSpace* space,
                                       SweeperType sweeper) {
   space->set_was_swept_conservatively(sweeper == CONSERVATIVE ||
                                       sweeper == LAZY_CONSERVATIVE);
 
   space->ClearStats();
@@ skipping 53 matching lines @@
           SweepPrecisely<SWEEP_ONLY, REBUILD_SKIP_LIST>(space, p, NULL);
         } else {
           SweepPrecisely<SWEEP_ONLY, IGNORE_SKIP_LIST>(space, p, NULL);
         }
         break;
       }
       default: {
         UNREACHABLE();
       }
     }
+    space->heap()->UpdateVisualizers(p);
   }
 }
 
 
 void MarkCompactCollector::SweepSpaces() {
   GCTracer::Scope gc_scope(tracer_, GCTracer::Scope::MC_SWEEP);
 #ifdef DEBUG
   state_ = SWEEP_SPACES;
 #endif
   SweeperType how_to_sweep =
@@ skipping 195 matching lines @@
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 
 
 } }  // namespace v8::internal