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

test/cctest/compiler/test-js-constant-cache.cc

 // 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.
 
 #include "src/v8.h"
 
 #include "src/assembler.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/node-properties.h"
 #include "src/compiler/typer.h"
@@ skipping 29 matching lines @@
       : JSCacheTesterHelper(main_isolate(), main_zone()),
         JSGraph(main_isolate(), &main_graph_, &main_common_, &main_javascript_,
                 &main_machine_) {
     main_graph_.SetStart(main_graph_.NewNode(common()->Start(0)));
     main_graph_.SetEnd(main_graph_.NewNode(common()->End(1)));
     main_typer_.Run();
   }
 
   Type* upper(Node* node) { return NodeProperties::GetBounds(node).upper; }
 
-  Handle<Object> handle(Node* node) {
+  Handle<HeapObject> handle(Node* node) {
     CHECK_EQ(IrOpcode::kHeapConstant, node->opcode());
-    return OpParameter<Unique<Object> >(node).handle();
+    return OpParameter<Handle<HeapObject>>(node);
   }
 
   Factory* factory() { return main_isolate()->factory(); }
 };
 
 
 TEST(ZeroConstant1) {
   JSConstantCacheTester T;
 
   Node* zero = T.ZeroConstant();
@@ skipping 402 matching lines @@
       T.Constant(1.11),
       T.ExternalConstant(ExternalReference::address_of_one_half())};
 
   NodeVector nodes(T.main_zone());
   T.GetCachedNodes(&nodes);
 
   for (size_t i = 0; i < arraysize(constants); i++) {
     CHECK(Contains(&nodes, constants[i]));
   }
 }