Add new style of string interpolation optimization: new nodes, working constant folding.

runtime/vm/ast_printer.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_printer.h"
 
 #include "vm/handles.h"
 #include "vm/object.h"
 #include "vm/os.h"
 #include "vm/parser.h"
@@ skipping 106 matching lines @@
 void AstPrinter::VisitLetNode(LetNode* node) {
   VisitGenericAstNode(node);
 }
 
 
 void AstPrinter::VisitArrayNode(ArrayNode* node) {
   VisitGenericAstNode(node);
 }
 
 
+void AstPrinter::VisitStringInterpolateNode(StringInterpolateNode* node) {
+  VisitGenericAstNode(node);
+}
+
+
 void AstPrinter::VisitLiteralNode(LiteralNode* node) {
   const Instance& literal = node->literal();
   OS::Print("(%s \"%s\")", node->PrettyName(), literal.ToCString());
 }
 
 
 void AstPrinter::VisitTypeNode(TypeNode* node) {
   const AbstractType& type = node->type();
   OS::Print("(%s \"%s\")",
             node->PrettyName(),
@@ skipping 347 matching lines @@
   ASSERT(node_sequence != NULL);
   AstPrinter ast_printer;
   const char* function_name =
       parsed_function.function().ToFullyQualifiedCString();
   OS::Print("Ast for function '%s' {\n", function_name);
   node_sequence->Visit(&ast_printer);
   OS::Print("}\n");
 }
 
 }  // namespace dart