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

src/debug/arm64/debug-arm64.cc

 // Copyright 2013 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_ARM64
 
 #include "src/arm64/frames-arm64.h"
 #include "src/codegen.h"
 #include "src/debug/debug.h"
 
@@ skipping 106 matching lines @@
   // 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());
   __ Mov(scratch, after_break_target);
   __ Ldr(scratch, MemOperand(scratch));
   __ Br(scratch);
 }
 
 
-void DebugCodegen::GeneratePlainReturnLiveEdit(MacroAssembler* masm) {
-  __ Ret();
-}
-
-
 void DebugCodegen::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
-  ExternalReference restarter_frame_function_slot =
-      ExternalReference::debug_restarter_frame_function_pointer_address(
-          masm->isolate());
-  UseScratchRegisterScope temps(masm);
-  Register scratch = temps.AcquireX();
-
-  __ Mov(scratch, restarter_frame_function_slot);
-  __ Str(xzr, MemOperand(scratch));
-
   // We do not know our frame height, but set sp based on fp.
   __ Sub(masm->StackPointer(), fp, kPointerSize);
   __ AssertStackConsistency();
 
   __ Pop(x1, fp, lr);  // Function, Frame, Return address.
 
+  ParameterCount dummy(0);
+  __ FloodFunctionIfStepping(x1, no_reg, dummy, dummy);
+
+  UseScratchRegisterScope temps(masm);
+  Register scratch = temps.AcquireX();
+
   // Load context from the function.
   __ Ldr(cp, FieldMemOperand(x1, JSFunction::kContextOffset));
 
   // Clear new.target as a safety measure.
   __ LoadRoot(x3, Heap::kUndefinedValueRootIndex);
 
   // Get function code.
   __ Ldr(scratch, FieldMemOperand(x1, JSFunction::kSharedFunctionInfoOffset));
   __ Ldr(scratch, FieldMemOperand(scratch, SharedFunctionInfo::kCodeOffset));
   __ Add(scratch, scratch, Code::kHeaderSize - kHeapObjectTag);
 
   // Re-run JSFunction, x1 is function, cp is context.
   __ Br(scratch);
 }
 
 
 const bool LiveEdit::kFrameDropperSupported = true;
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM64