Add some interfaces to the GC that allow us to reserve space. This is needed...

src/mark-compact.h

 // Copyright 2006-2008 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 74 matching lines @@
   // choosing spaces to compact.
   static void Prepare(GCTracer* tracer);
 
   // Performs a global garbage collection.
   static void CollectGarbage();
 
   // True if the last full GC performed heap compaction.
   static bool HasCompacted() { return compacting_collection_; }
 
   // True after the Prepare phase if the compaction is taking place.
-  static bool IsCompacting() { return compacting_collection_; }
+  static bool IsCompacting() {
+    return state_ != IDLE && compacting_collection_;
+  }
 
   // The count of the number of objects left marked at the end of the last
   // completed full GC (expected to be zero).
   static int previous_marked_count() { return previous_marked_count_; }
 
   // During a full GC, there is a stack-allocated GCTracer that is used for
   // bookkeeping information.  Return a pointer to that tracer.
   static GCTracer* tracer() { return tracer_; }
 
 #ifdef DEBUG
@@ skipping 319 matching lines @@
 
   friend class UnmarkObjectVisitor;
   static void UnmarkObject(HeapObject* obj);
 #endif
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_MARK_COMPACT_H_