Heap::gc_count_, last_gc_count, and kGCsBetweenCleanup should be unsigned...

src/heap.h

 // Copyright 2010 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 1123 matching lines @@
   static HeapState gc_state_;
 
   // Returns the size of object residing in non new spaces.
   static intptr_t PromotedSpaceSize();
 
   // Returns the amount of external memory registered since last global gc.
   static int PromotedExternalMemorySize();
 
   static int mc_count_;  // how many mark-compact collections happened
   static int ms_count_;  // how many mark-sweep collections happened
-  static int gc_count_;  // how many gc happened
+  static unsigned int gc_count_;  // how many gc happened
 
   // Total length of the strings we failed to flatten since the last GC.
   static int unflattened_strings_length_;
 
 #define ROOT_ACCESSOR(type, name, camel_name)                                  \
   static inline void set_##name(type* value) {                                 \
     roots_[k##camel_name##RootIndex] = value;                                  \
   }
   ROOT_LIST(ROOT_ACCESSOR)
 #undef ROOT_ACCESSOR
@@ skipping 951 matching lines @@
   // Return whether this object should be retained. If NULL is returned the
   // object has no references. Otherwise the address of the retained object
   // should be returned as in some GC situations the object has been moved.
   virtual Object* RetainAs(Object* object) = 0;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_H_