Fix build on arm and x64.

src/arm/virtual-frame-arm.cc

 // Copyright 2009 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 404 matching lines @@
     FrameElement dropped = elements_.RemoveLast();
     if (dropped.is_register()) {
       Unuse(dropped.reg());
     }
   }
 }
 
 
 Result VirtualFrame::Pop() {
   UNIMPLEMENTED();
-  Result invalid(cgen_);
-  return invalid;
+  return Result();
 }
 
 
 void VirtualFrame::EmitPop(Register reg) {
   ASSERT(stack_pointer_ == elements_.length() - 1);
   stack_pointer_--;
   elements_.RemoveLast();
   __ pop(reg);
 }
 
 
 void VirtualFrame::EmitPush(Register reg) {
   ASSERT(stack_pointer_ == elements_.length() - 1);
   elements_.Add(FrameElement::MemoryElement());
   stack_pointer_++;
   __ push(reg);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal