Fix 'step in' after live edit stack manipulation

src/x64/debug-x64.cc

 // Copyright 2010 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 195 matching lines @@
 }
 
 
 void Debug::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
   masm->Abort("LiveEdit frame dropping is not supported on x64");
 }
 
 #undef __
 
 
-void Debug::SetUpFrameDropperFrame(StackFrame* bottom_js_frame,
-                                   Handle<Code> code) {
+Object** Debug::SetUpFrameDropperFrame(StackFrame* bottom_js_frame,
+                                       Handle<Code> code) {
   UNREACHABLE();
+  return NULL;
 }
 const int Debug::kFrameDropperFrameSize = -1;
 
 
 void BreakLocationIterator::ClearDebugBreakAtReturn() {
   rinfo()->PatchCode(original_rinfo()->pc(),
                      Assembler::kJSReturnSequenceLength);
 }
 
 
@@ skipping 29 matching lines @@
   ASSERT(IsDebugBreakSlot());
   rinfo()->PatchCode(original_rinfo()->pc(), Assembler::kDebugBreakSlotLength);
 }
 
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64