Remove unused code for StringConcatNode from the AST and the graph builder.

vm/ast.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/ast.h"
 #include "vm/compiler.h"
 #include "vm/dart_entry.h"
 #include "vm/isolate.h"
 #include "vm/object_store.h"
 
@@ skipping 165 matching lines @@
       return false;
   }
 }
 
 
 const char* BinaryOpNode::Name() const {
   return Token::Str(kind_);
 }
 
 
-const Instance* StringConcatNode::EvalConstExpr() const {
-  for (int i = 0; i < values()->length(); i++) {
-    if (!values()->ElementAt(i)->IsLiteralNode()) {
-      return NULL;
-    }
-  }
-  // All nodes are literals, so this is a compile time constant string.
-  // We just return the first literal as value approximation.
-  return &values()->ElementAt(0)->AsLiteralNode()->literal();
-}
-
-
 const Instance* BinaryOpNode::EvalConstExpr() const {
   const Instance* left_val = this->left()->EvalConstExpr();
   if (left_val == NULL) {
     return NULL;
   }
   if (!left_val->IsNumber() && !left_val->IsBool()) {
     return NULL;
   }
   const Instance* right_val = this->right()->EvalConstExpr();
   if (right_val == NULL) {
@@ skipping 172 matching lines @@
   if (result.IsError() || result.IsNull()) {
     // TODO(turnidge): We could get better error messages by returning
     // the Error object directly to the parser.  This will involve
     // replumbing all of the EvalConstExpr methods.
     return NULL;
   }
   return &Instance::ZoneHandle(Instance::Cast(result).raw());
 }
 
 }  // namespace dart