[turbofan] Remove usage of Unique<T> from graph.

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 54 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* UndefinedConstant() {
-    Unique<HeapObject> unique = Unique<HeapObject>::CreateImmovable(
-        isolate()->factory()->undefined_value());
-    return NewNode(common()->HeapConstant(unique));
+    Handle<HeapObject> undefined = isolate()->factory()->undefined_value();
+    return NewNode(common()->HeapConstant(undefined));
   }
 
   // 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.
     return kPointerSize == 8 ? Int64Constant(value)
                              : Int32Constant(static_cast<int>(value));
   }
   Node* Int32Constant(int32_t value) {
     return NewNode(common()->Int32Constant(value));
   }
   Node* Int64Constant(int64_t value) {
     return NewNode(common()->Int64Constant(value));
   }
   Node* NumberConstant(double value) {
     return NewNode(common()->NumberConstant(value));
   }
   Node* Float32Constant(float value) {
     return NewNode(common()->Float32Constant(value));
   }
   Node* Float64Constant(double value) {
     return NewNode(common()->Float64Constant(value));
   }
   Node* HeapConstant(Handle<HeapObject> object) {
-    Unique<HeapObject> val = Unique<HeapObject>::CreateUninitialized(object);
-    return NewNode(common()->HeapConstant(val));
-  }
-  Node* HeapConstant(Unique<HeapObject> object) {
     return NewNode(common()->HeapConstant(object));
   }
   Node* ExternalConstant(ExternalReference address) {
     return NewNode(common()->ExternalConstant(address));
   }
 
   Node* Projection(int index, Node* a) {
     return NewNode(common()->Projection(index), a);
   }
 
@@ skipping 473 matching lines @@
   BasicBlock* current_block_;
 
   DISALLOW_COPY_AND_ASSIGN(RawMachineAssembler);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_RAW_MACHINE_ASSEMBLER_H_