Make proxy fixing GC safe.

src/runtime.cc

 // 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 601 matching lines @@
   ASSERT(args.length() == 1);
   CONVERT_CHECKED(JSProxy, proxy, args[0]);
   return proxy->handler();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_Fix) {
   ASSERT(args.length() == 1);
   CONVERT_CHECKED(JSProxy, proxy, args[0]);
   proxy->Fix();
-  return proxy;
+  return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_ClassOf) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
   Object* obj = args[0];
   if (!obj->IsJSObject()) return isolate->heap()->null_value();
   return JSObject::cast(obj)->class_name();
 }
@@ skipping 12062 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(false);
   }
 }
 
 
 } }  // namespace v8::internal