Revert of [debugger] remove debugger statement support from FCG/CS.

src/x64/macro-assembler-x64.h

 // 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.
 
 #ifndef V8_X64_MACRO_ASSEMBLER_X64_H_
 #define V8_X64_MACRO_ASSEMBLER_X64_H_
 
 #include "src/assembler.h"
 #include "src/bailout-reason.h"
 #include "src/base/flags.h"
@@ skipping 305 matching lines @@
   void RecordWrite(
       Register object,
       Register address,
       Register value,
       SaveFPRegsMode save_fp,
       RememberedSetAction remembered_set_action = EMIT_REMEMBERED_SET,
       SmiCheck smi_check = INLINE_SMI_CHECK,
       PointersToHereCheck pointers_to_here_check_for_value =
           kPointersToHereMaybeInteresting);
 
-  // Frame restart support.
+  // ---------------------------------------------------------------------------
+  // Debugger Support
+
+  void DebugBreak();
   void MaybeDropFrames();
 
   // Generates function and stub prologue code.
   void StubPrologue(StackFrame::Type type);
   void Prologue(bool code_pre_aging);
 
   // Enter specific kind of exit frame; either in normal or
   // debug mode. Expects the number of arguments in register rax and
   // sets up the number of arguments in register rdi and the pointer
   // to the first argument in register rsi.
@@ skipping 1348 matching lines @@
 inline Operand StackOperandForReturnAddress(int32_t disp) {
   return Operand(rsp, disp);
 }
 
 #define ACCESS_MASM(masm) masm->
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_X64_MACRO_ASSEMBLER_X64_H_