Run Crankshaft on a separate thread.

src/handles.h

 // Copyright 2011 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 138 matching lines @@
   Isolate* isolate_;
   Object** prev_next_;
   Object** prev_limit_;
 
   // Extend the handle scope making room for more handles.
   static internal::Object** Extend();
 
   // Zaps the handles in the half-open interval [start, end).
   static void ZapRange(internal::Object** start, internal::Object** end);
 
+  bool has_isolate_lock_;
+
   friend class v8::HandleScope;
   friend class v8::ImplementationUtilities;
 };
 
 
 // ----------------------------------------------------------------------------
 // Handle operations.
 // They might invoke garbage collection. The result is an handle to
 // an object of expected type, or the handle is an error if running out
 // of space or encountering an internal error.
@@ skipping 124 matching lines @@
   inline NoHandleAllocation();
   inline ~NoHandleAllocation();
  private:
   int level_;
 #endif
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_HANDLES_H_