Making save a little faster:

compiler/java/com/google/dart/compiler/ast/DartNode.java

 // Copyright (c) 2012, 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.
 
 package com.google.dart.compiler.ast;
 
 import com.google.dart.compiler.common.AbstractNode;
 import com.google.dart.compiler.resolver.Element;
 import com.google.dart.compiler.type.Type;
 import com.google.dart.compiler.util.DefaultTextOutput;
@@ skipping 23 matching lines @@
 
   public void setType(Type type) {
     this.type = type;
   }
 
   public Type getType() {
     return type;
   }
 
   @Override
-  public final String toString() {
+  public String toString() {
     return this.toSource();
   }
 
   /**
    * Returns this node's parent node, or <code>null</code> if this is the
    * root node.
    * <p>
    * Note that the relationship between an AST node and its parent node
    * may change over the lifetime of a node.
    *
@@ skipping 55 matching lines @@
     return super.toString();
   }
 
   /**
    * If the given child is not <code>null</code>, use the given visitor to visit it.
    * 
    * @param child the child to be visited
    * @param visitor the visitor that will be used to visit the child
    */
   protected void safelyVisitChild(DartNode child, ASTVisitor<?> visitor) {
-    if (child != null) {
+    // Inline the DartIdentifier path - it's by far the most common.
+    if (child instanceof DartIdentifier) {
+      visitor.visitIdentifier((DartIdentifier)child);
+    } else if (child != null) {
       child.accept(visitor);
     }
   }
   
 }