NewGC: Merge bleeding edge up to 9009.

src/zone.h

Index: src/zone.h
===================================================================
--- src/zone.h	(revision 9006)
+++ src/zone.h	(working copy)
@@ -65,9 +65,13 @@
   template <typename T>
   inline T* NewArray(int length);
 
-  // Delete all objects and free all memory allocated in the Zone.
+  // Deletes all objects and free all memory allocated in the Zone. Keeps one
+  // small (size <= kMaximumKeptSegmentSize) segment around if it finds one.
   void DeleteAll();
 
+  // Deletes the last small segment kept around by DeleteAll().
+  void DeleteKeptSegment();
+
   // Returns true if more memory has been allocated in zones than
   // the limit allows.
   inline bool excess_allocation();
@@ -196,10 +200,6 @@
 };
 
 
-// Introduce a convenience type for zone lists of map handles.
-typedef ZoneList<Handle<Map> > ZoneMapList;
-
-
 // ZoneScopes keep track of the current parsing and compilation
 // nesting and cleans up generated ASTs in the Zone when exiting the
 // outer-most scope.