[crankshaft] Remove the useless HMapEnumLength instruction.

src/crankshaft/hydrogen.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_CRANKSHAFT_HYDROGEN_H_
 #define V8_CRANKSHAFT_HYDROGEN_H_
 
 #include "src/accessors.h"
 #include "src/allocation.h"
 #include "src/ast/ast.h"
@@ skipping 1280 matching lines @@
   HValue* BuildDecodeField(HValue* encoded_field) {
     HValue* mask_value = Add<HConstant>(static_cast<int>(BitFieldClass::kMask));
     HValue* masked_field =
         AddUncasted<HBitwise>(Token::BIT_AND, encoded_field, mask_value);
     return AddUncasted<HShr>(masked_field,
         Add<HConstant>(static_cast<int>(BitFieldClass::kShift)));
   }
 
   HValue* BuildGetElementsKind(HValue* object);
 
+  HValue* BuildEnumLength(HValue* map);
+
   HValue* BuildCheckHeapObject(HValue* object);
   HValue* BuildCheckString(HValue* string);
   HValue* BuildWrapReceiver(HValue* object, HValue* function);
 
   // Building common constructs
   HValue* BuildCheckForCapacityGrow(HValue* object,
                                     HValue* elements,
                                     ElementsKind kind,
                                     HValue* length,
                                     HValue* key,
@@ skipping 1750 matching lines @@
 
  private:
   HGraphBuilder* builder_;
 };
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_CRANKSHAFT_HYDROGEN_H_