Minor simplification and cleanup of graph builder.

test/cctest/compiler/simplified-graph-builder.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_SIMPLIFIED_GRAPH_BUILDER_H_
 #define V8_CCTEST_COMPILER_SIMPLIFIED_GRAPH_BUILDER_H_
 
 #include "src/compiler/common-operator.h"
 #include "src/compiler/graph-builder.h"
 #include "src/compiler/machine-node-factory.h"
@@ skipping 31 matching lines @@
   };
 
   Isolate* isolate() const { return zone()->isolate(); }
   Zone* zone() const { return StructuredGraphBuilder::zone(); }
   CommonOperatorBuilder* common() const {
     return StructuredGraphBuilder::common();
   }
   MachineOperatorBuilder* machine() const { return machine_; }
   SimplifiedOperatorBuilder* simplified() const { return simplified_; }
   Environment* environment() {
-    return reinterpret_cast<Environment*>(environment_internal());
+    return reinterpret_cast<Environment*>(
+        StructuredGraphBuilder::environment());
   }
 
   // Initialize graph and builder.
   void Begin(int num_parameters);
 
   void Return(Node* value);
 
   // Close the graph.
   void End();
 
  private:
   MachineOperatorBuilder* machine_;
   SimplifiedOperatorBuilder* simplified_;
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_CCTEST_COMPILER_SIMPLIFIED_GRAPH_BUILDER_H_