Remove deprecated StringBuffer.add, addAll and addCharCode.

samples/tests/samples/chat/chat_server_test.dart

Index: samples/tests/samples/chat/chat_server_test.dart
diff --git a/samples/tests/samples/chat/chat_server_test.dart b/samples/tests/samples/chat/chat_server_test.dart
index 2b7361f0b7d6315a07e9f582adaee5094f442876..57a275d488e97b8e9e6354954b5a8dfb70b1508c 100644
--- a/samples/tests/samples/chat/chat_server_test.dart
+++ b/samples/tests/samples/chat/chat_server_test.dart
@@ -72,7 +72,7 @@ class ChatTestClient {
       .then((HttpClientResponse response) {
         StringBuffer body = new StringBuffer();
         response.listen(
-          (data) => body.add(new String.fromCharCodes(data)),
+          (data) => body.write(new String.fromCharCodes(data)),
           onDone: () => leaveResponseHandler(response, body.toString()));
       });
   }
@@ -128,7 +128,7 @@ class ChatTestClient {
       .then((HttpClientResponse response) {
         StringBuffer body = new StringBuffer();
         response.listen(
-          (data) => body.add(new String.fromCharCodes(data)),
+          (data) => body.write(new String.fromCharCodes(data)),
           onDone: () => receiveResponseHandler(response, body.toString()));
       });
   }
@@ -158,7 +158,7 @@ class ChatTestClient {
       .then((HttpClientResponse response) {
         StringBuffer body = new StringBuffer();
         response.listen(
-          (data) => body.add(new String.fromCharCodes(data)),
+          (data) => body.write(new String.fromCharCodes(data)),
           onDone: () => sendResponseHandler(response, body.toString()));
       });
   }
@@ -189,7 +189,7 @@ class ChatTestClient {
       .then((HttpClientResponse response) {
         StringBuffer body = new StringBuffer();
         response.listen(
-          (data) => body.add(new String.fromCharCodes(data)),
+          (data) => body.write(new String.fromCharCodes(data)),
           onDone: () => joinResponseHandler(response, body.toString()));
       });
   }