Make start node a value input to parameter nodes.

test/cctest/compiler/graph-tester.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_CCTEST_COMPILER_GRAPH_TESTER_H_
 #define V8_CCTEST_COMPILER_GRAPH_TESTER_H_
 
 #include "src/v8.h"
 #include "test/cctest/cctest.h"
 
 #include "src/compiler/common-operator.h"
 #include "src/compiler/graph.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 class GraphTester : public HandleAndZoneScope, public Graph {
  public:
   GraphTester() : Graph(main_zone()) {}
 };
 
 
 class GraphWithStartNodeTester : public GraphTester {
  public:
-  GraphWithStartNodeTester()
-      : builder_(main_zone()), start_node_(NewNode(builder_.Start())) {
+  explicit GraphWithStartNodeTester(int num_parameters = 0)
+      : builder_(main_zone()),
+        start_node_(NewNode(builder_.Start(num_parameters))) {
     SetStart(start_node_);
   }
 
   Node* start_node() { return start_node_; }
 
  private:
   CommonOperatorBuilder builder_;
   Node* start_node_;
 };
 }
 }
 }  // namespace v8::internal::compiler
 
 #endif  // V8_CCTEST_COMPILER_GRAPH_TESTER_H_