Remove deprecated StringBuffer.add, addAll and addCharCode.

samples/tests/samples/lib/layout/grid_layout_demo.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.
 
 part of layout_tests;
 
 /**
  * An app for testing the grid layout system.
  */
 
@@ skipping 19 matching lines @@
   if (query != null && query.length == 1) {
     query = Uri.decodeComponent(query[0]);
     addGridStyles('100%', '100%', 'margin:0px;');
     final view = createGrid(GridExamples.styles[query]);
     view.addToDocument(document.body);
     _addColorStyles();
     printMetrics(query);
   } else {
     final html = new StringBuffer();
     for (String ex in GridExamples.styles.keys) {
-      html.add('<div><a href="?q=$ex">Grid Example $ex</a></div>');
+      html.write('<div><a href="?q=$ex">Grid Example $ex</a></div>');
     }
     document.body.innerHTML = html.toString();
   }
 }
 
 void addGridStyles(String width, String height, [String margin = '']) {
   // Use monospace font and fixed line-height so the text size is predictable.
   // TODO(jmesserly): only tested on Chromium Mac/Linux
   Dom.addStyle('''
     body { $margin }
@@ skipping 48 matching lines @@
     // TODO(jmesserly): this is needed to get horizontal content-sizing to work
     node.style.display = 'inline-block';
   }
 }
 
 
 void printMetrics(String example) {
   final node = document.body.query('#grid');
   String exampleId = example.split(' ')[0];
   final sb = new StringBuffer();
-  sb.add("test('Spec Example $exampleId', () {\n");
-  sb.add("  verifyExample('$example', {\n");
+  sb.write("test('Spec Example $exampleId', () {\n");
+  sb.write("  verifyExample('$example', {\n");
   final children = node.children;
 
   window.setImmediate(() {
     for (int i = 0; i < children.length; i++) {
       _appendMetrics(sb, children[i], '    ');
     }
-    sb.add('  });\n');
-    sb.add('});\n\n');
+    sb.write('  });\n');
+    sb.write('});\n\n');
     window.console.log(sb.toString());
   });
 }
 
 void _appendMetrics(StringBuffer sb, Element node, [String indent = '']) {
   String id = node.id;
   num left = node.offsetLeft, top = node.offsetTop;
   num width = node.offsetWidth, height = node.offsetHeight;
-  sb.add("${indent}'$id': [$left, $top, $width, $height],\n");
+  sb.write("${indent}'$id': [$left, $top, $width, $height],\n");
 }