Fix win64 compilation (using static_cast)

src/frames.cc

 // 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 298 matching lines @@
 bool StackFrame::HasHandler() const {
   StackHandlerIterator it(this, top_handler());
   return !it.done();
 }
 
 void StackFrame::IteratePc(ObjectVisitor* v,
                            Address* pc_address,
                            Code* holder) {
   Address pc = *pc_address;
   ASSERT(holder->contains(pc));
-  unsigned pc_offset = pc - holder->instruction_start();
+  unsigned pc_offset = static_cast<unsigned>(pc - holder->instruction_start());
   Object* code = holder;
   v->VisitPointer(&code);
   if (code != holder) {
     holder = reinterpret_cast<Code*>(code);
     pc = holder->instruction_start() + pc_offset;
     *pc_address = pc;
   }
 }
 
 
@@ skipping 568 matching lines @@
   ZoneList<StackFrame*> list(10);
   for (StackFrameIterator it; !it.done(); it.Advance()) {
     StackFrame* frame = AllocateFrameCopy(it.frame());
     list.Add(frame);
   }
   return list.ToVector();
 }
 
 
 } }  // namespace v8::internal