Fix newly discovered presubmit errors.

src/arm64/macro-assembler-arm64.h

 // 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.
 
 #ifndef V8_ARM64_MACRO_ASSEMBLER_ARM64_H_
 #define V8_ARM64_MACRO_ASSEMBLER_ARM64_H_
 
 #include <vector>
 
 #include "src/globals.h"
@@ skipping 2183 matching lines @@
                                              ImmBranchType branch_type);
 };
 
 
 // Use this scope when you need a one-to-one mapping bewteen methods and
 // instructions. This scope prevents the MacroAssembler from being called and
 // literal pools from being emitted. It also asserts the number of instructions
 // emitted is what you specified when creating the scope.
 class InstructionAccurateScope BASE_EMBEDDED {
  public:
-  InstructionAccurateScope(MacroAssembler* masm, size_t count = 0)
+  explicit InstructionAccurateScope(MacroAssembler* masm, size_t count = 0)
       : masm_(masm)
 #ifdef DEBUG
         ,
         size_(count * kInstructionSize)
 #endif
   {
     // Before blocking the const pool, see if it needs to be emitted.
     masm_->CheckConstPool(false, true);
     masm_->CheckVeneerPool(false, true);
 
@@ skipping 139 matching lines @@
 #error "Unsupported option"
 #define CODE_COVERAGE_STRINGIFY(x) #x
 #define CODE_COVERAGE_TOSTRING(x) CODE_COVERAGE_STRINGIFY(x)
 #define __FILE_LINE__ __FILE__ ":" CODE_COVERAGE_TOSTRING(__LINE__)
 #define ACCESS_MASM(masm) masm->stop(__FILE_LINE__); masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 #endif  // V8_ARM64_MACRO_ASSEMBLER_ARM64_H_