Revert of [debugger] do not predict step in target for liveedit.

src/debug/x64/debug-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/assembler.h"
 #include "src/codegen.h"
 #include "src/debug/debug.h"
 
@@ skipping 88 matching lines @@
   // Now that the break point has been handled, resume normal execution by
   // jumping to the target address intended by the caller and that was
   // overwritten by the address of DebugBreakXXX.
   ExternalReference after_break_target =
       ExternalReference::debug_after_break_target_address(masm->isolate());
   __ Move(kScratchRegister, after_break_target);
   __ Jump(Operand(kScratchRegister, 0));
 }
 
 
+void DebugCodegen::GeneratePlainReturnLiveEdit(MacroAssembler* masm) {
+  masm->ret(0);
+}
+
+
 void DebugCodegen::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
+  ExternalReference restarter_frame_function_slot =
+      ExternalReference::debug_restarter_frame_function_pointer_address(
+          masm->isolate());
+  __ Move(rax, restarter_frame_function_slot);
+  __ movp(Operand(rax, 0), Immediate(0));
+
   // We do not know our frame height, but set rsp based on rbp.
   __ leap(rsp, Operand(rbp, -1 * kPointerSize));
 
   __ Pop(rdi);  // Function.
   __ popq(rbp);
 
-  ParameterCount dummy(0);
-  __ FloodFunctionIfStepping(rdi, no_reg, dummy, dummy);
-
   // Load context from the function.
   __ movp(rsi, FieldOperand(rdi, JSFunction::kContextOffset));
 
   // Clear new.target as a safety measure.
   __ LoadRoot(rdx, Heap::kUndefinedValueRootIndex);
 
   // Get function code.
   __ movp(rbx, FieldOperand(rdi, JSFunction::kSharedFunctionInfoOffset));
   __ movp(rbx, FieldOperand(rbx, SharedFunctionInfo::kCodeOffset));
   __ leap(rbx, FieldOperand(rbx, Code::kHeaderSize));
 
   // Re-run JSFunction, rdi is function, rsi is context.
   __ jmp(rbx);
 }
 
 const bool LiveEdit::kFrameDropperSupported = true;
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64