[Interpreter] Add support for for..in.

src/compiler/raw-machine-assembler.h

 // Copyright 2014 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_COMPILER_RAW_MACHINE_ASSEMBLER_H_
 #define V8_COMPILER_RAW_MACHINE_ASSEMBLER_H_
 
 #include "src/assembler.h"
 #include "src/compiler/common-operator.h"
 #include "src/compiler/graph.h"
@@ skipping 57 matching lines @@
 
   // Finalizes the schedule and exports it to be used for code generation. Note
   // that this RawMachineAssembler becomes invalid after export.
   Schedule* Export();
 
   // ===========================================================================
   // The following utility methods create new nodes with specific operators and
   // place them into the current basic block. They don't perform control flow,
   // hence will not switch the current basic block.
 
+  Node* NullConstant() {
+    return HeapConstant(isolate()->factory()->null_value());
+  }
+
   Node* UndefinedConstant() {
     return HeapConstant(isolate()->factory()->undefined_value());
   }
 
   // Constants.
   Node* PointerConstant(void* value) {
     return IntPtrConstant(reinterpret_cast<intptr_t>(value));
   }
   Node* IntPtrConstant(intptr_t value) {
     // TODO(dcarney): mark generated code as unserializable if value != 0.
@@ skipping 512 matching lines @@
   BasicBlock* current_block_;
 
   DISALLOW_COPY_AND_ASSIGN(RawMachineAssembler);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_RAW_MACHINE_ASSEMBLER_H_