Add GCTracer metrics for a scavenger GC for DOM wrappers

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 2531 matching lines @@
   // Sets the GC count.
   void set_gc_count(unsigned int count) { gc_count_ = count; }
 
   // Sets the full GC count.
   void set_full_gc_count(int count) { full_gc_count_ = count; }
 
   void increment_promoted_objects_size(int object_size) {
     promoted_objects_size_ += object_size;
   }
 
+  void increment_nodes_died_in_new_space() {
+    nodes_died_in_new_space_++;
+  }
+
+  void increment_nodes_copied_in_new_space() {
+    nodes_copied_in_new_space_++;
+  }
+
+  void increment_nodes_promoted() {
+    nodes_promoted_++;
+  }
+
  private:
   // Returns a string matching the collector.
   const char* CollectorString();
 
   // Returns size of object in heap (in MB).
   inline double SizeOfHeapObjects();
 
   // Timestamp set in the constructor.
   double start_time_;
 
@@ skipping 24 matching lines @@
   // collection and the end of the previous collection.
   intptr_t allocated_since_last_gc_;
 
   // Amount of time spent in mutator that is time elapsed between end of the
   // previous collection and the beginning of the current one.
   double spent_in_mutator_;
 
   // Size of objects promoted during the current collection.
   intptr_t promoted_objects_size_;
 
+  // Number of died nodes in the new space.
+  int nodes_died_in_new_space_;
+
+  // Number of copied nodes to the new space.
+  int nodes_copied_in_new_space_;
+
+  // Number of promoted nodes to the old space.
+  int nodes_promoted_;
+
   // Incremental marking steps counters.
   int steps_count_;
   double steps_took_;
   double longest_step_;
   int steps_count_since_last_gc_;
   double steps_took_since_last_gc_;
 
   Heap* heap_;
 
   const char* gc_reason_;
@@ skipping 210 matching lines @@
   AssertNoAllocation no_alloc;  // i.e. no gc allowed.
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG || LIVE_OBJECT_LIST
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_H_