Adding GC hooks to support LiveObjectList functionality.

src/mark-compact.cc

Index: src/mark-compact.cc
===================================================================
--- src/mark-compact.cc	(revision 6377)
+++ src/mark-compact.cc	(working copy)
@@ -33,6 +33,7 @@
 #include "gdb-jit.h"
 #include "global-handles.h"
 #include "ic-inl.h"
+#include "liveobjectlist-inl.h"
 #include "mark-compact.h"
 #include "objects-visiting.h"
 #include "stub-cache.h"
@@ -1660,6 +1661,7 @@
         free_start = current;
         is_prev_alive = false;
       }
+      LiveObjectList::ProcessNonLive(object);
     }
   }
 
@@ -1880,6 +1882,9 @@
                     size,
                     false);
     } else {
+      // Process the dead object before we write a NULL into its header.
+      LiveObjectList::ProcessNonLive(object);
+
       size = object->Size();
       Memory::Address_at(current) = NULL;
     }
@@ -1899,6 +1904,7 @@
 
   // Update roots.
   Heap::IterateRoots(&updating_visitor, VISIT_ALL_IN_SCAVENGE);
+  LiveObjectList::IterateElements(&updating_visitor);
 
   // Update pointers in old spaces.
   Heap::IterateDirtyRegions(Heap::old_pointer_space(),
@@ -1986,6 +1992,7 @@
           free_start = current;
           is_previous_alive = false;
         }
+        LiveObjectList::ProcessNonLive(object);
       }
       // The object is now unmarked for the call to Size() at the top of the
       // loop.
@@ -2164,6 +2171,7 @@
   void UpdateMapPointersInRoots() {
     Heap::IterateRoots(&map_updating_visitor_, VISIT_ONLY_STRONG);
     GlobalHandles::IterateWeakRoots(&map_updating_visitor_);
+    LiveObjectList::IterateElements(&map_updating_visitor_);
   }
 
   void UpdateMapPointersInPagedSpace(PagedSpace* space) {
@@ -2533,6 +2541,8 @@
   // Update the pointer to the head of the weak list of global contexts.
   updating_visitor.VisitPointer(&Heap::global_contexts_list_);
 
+  LiveObjectList::IterateElements(&updating_visitor);
+
   int live_maps_size = IterateLiveObjects(Heap::map_space(),
                                           &UpdatePointersInOldObject);
   int live_pointer_olds_size = IterateLiveObjects(Heap::old_pointer_space(),