Remove deprecated StringBuffer.add, addAll and addCharCode.

utils/css/treebase.dart

 // 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.
 /**
  * The base type for all nodes in a dart abstract syntax tree.
  */
 class ASTNode {
   /** The source code this [ASTNode] represents. */
   SourceSpan span;
 
@@ skipping 39 matching lines @@
     var o = new TreeOutput();
     node.visit(new TreePrinter(o));
     print(o.buf);
   }
 
   TreeOutput(): this.depth = 0, this.buf = new StringBuffer() {
   }
 
   void write(String s) {
     for (int i=0; i < depth; i++) {
-      buf.add(' ');
+      buf.write(' ');
     }
-    buf.add(s);
+    buf.write(s);
   }
 
   void writeln(String s) {
     write(s);
-    buf.add('\n');
+    buf.write('\n');
   }
 
   void heading(String name, span) {
     write(name);
-    buf.add('  (${span.locationText})');
-    buf.add('\n');
+    buf.write('  (${span.locationText})');
+    buf.write('\n');
   }
 
   String toValue(value) {
     if (value == null) return 'null';
     else if (value is Identifier) return value.name;
     else return value.toString();
   }
 
   void writeNode(String label, ASTNode node) {
     write(label + ': ');
     depth += 1;
     if (node != null) node.visit(printer);
     else writeln('null');
     depth -= 1;
   }
 
   void writeValue(String label, value) {
     var v = toValue(value);
     writeln('${label}: ${v}');
   }
 
   void writeList(String label, List list) {
     write(label + ': ');
     if (list == null) {
-      buf.add('null');
-      buf.add('\n');
+      buf.write('null');
+      buf.write('\n');
     } else {
       for (var item in list) {
-        buf.add(item.toString());
-        buf.add(', ');
+        buf.write(item.toString());
+        buf.write(', ');
       }
-      buf.add('\n');
+      buf.write('\n');
     }
   }
 
   void writeNodeList(String label, List list) {
     writeln('${label} [');
     if (list != null) {
       depth += 1;
       for (var node in list) {
         if (node != null) {
           node.visit(printer);
         } else {
           writeln('null');
         }
       }
       depth -= 1;
       writeln(']');
     }
   }
 }