Fix newly discovered presubmit errors.

src/arm64/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_ASSEMBLER_ARM64_H_
 #define V8_ARM64_ASSEMBLER_ARM64_H_
 
 #include <list>
 #include <map>
 #include <vector>
@@ skipping 679 matching lines @@
   Register reg_;
   Shift shift_;
   Extend extend_;
   unsigned shift_amount_;
 };
 
 
 // MemOperand represents a memory operand in a load or store instruction.
 class MemOperand {
  public:
-  inline explicit MemOperand();
+  inline MemOperand();
   inline explicit MemOperand(Register base,
                              ptrdiff_t offset = 0,
                              AddrMode addrmode = Offset);
   inline explicit MemOperand(Register base,
                              Register regoffset,
                              Shift shift = LSL,
                              unsigned shift_amount = 0);
   inline explicit MemOperand(Register base,
                              Register regoffset,
                              Extend extend,
@@ skipping 1588 matching lines @@
 class EnsureSpace BASE_EMBEDDED {
  public:
   explicit EnsureSpace(Assembler* assembler) {
     assembler->CheckBufferSpace();
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM64_ASSEMBLER_ARM64_H_