Don't add code dependencies eagerly for HCheckMaps.

src/x64/lithium-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_LITHIUM_X64_H_
 #define V8_X64_LITHIUM_X64_H_
 
 #include "hydrogen.h"
 #include "lithium-allocator.h"
 #include "lithium.h"
@@ skipping 2320 matching lines @@
 
   LOperand* value() { return inputs_[0]; }
 
   DECLARE_CONCRETE_INSTRUCTION(CheckInstanceType, "check-instance-type")
   DECLARE_HYDROGEN_ACCESSOR(CheckInstanceType)
 };
 
 
 class LCheckMaps V8_FINAL : public LTemplateInstruction<0, 1, 0> {
  public:
-  explicit LCheckMaps(LOperand* value) {
+  explicit LCheckMaps(LOperand* value = NULL) {
     inputs_[0] = value;
   }
 
   LOperand* value() { return inputs_[0]; }
 
   DECLARE_CONCRETE_INSTRUCTION(CheckMaps, "check-maps")
   DECLARE_HYDROGEN_ACCESSOR(CheckMaps)
 };
 
 
@@ skipping 458 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(LChunkBuilder);
 };
 
 #undef DECLARE_HYDROGEN_ACCESSOR
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::int
 
 #endif  // V8_X64_LITHIUM_X64_H_