Fixed Issue 7508: Many StringBuffer methods return StringBuffer, but should be void.

tests/corelib/string_buffer_test.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.
 
 // TODO(srdjan): Move StringBuffer to visible names.
 
 class StringBufferTest {
   static testConstructor() {
     StringBuffer bf = new StringBuffer("");
     Expect.equals(true, bf.isEmpty);
@@ skipping 45 matching lines @@
     Expect.equals("abcdefghijklmnopqrstuvwxyz\n"
                   "thequickbrownfoxjumpsoverthelazydog",
                   bf.toString());
 
     bf = new StringBuffer("");
     for (int i = 0; i < 100000; i++) {
       bf.add('');
       bf.add("");
     }
     Expect.equals("", bf.toString());
-
-    Expect.equals(bf, bf.add("foo"));
   }
 
   static testLength() {
     StringBuffer bf = new StringBuffer("");
     Expect.equals(0, bf.length);
     bf.add("foo");
     Expect.equals(3, bf.length);
     bf.add("bar");
     Expect.equals(6, bf.length);
     bf.add("");
@@ skipping 10 matching lines @@
   static testAddAll() {
     StringBuffer bf = new StringBuffer("");
     bf.addAll(["foo", "bar", "a", "b", "c"]);
     Expect.equals("foobarabc", bf.toString());
 
     bf.addAll([]);
     Expect.equals("foobarabc", bf.toString());
 
     bf.addAll(["", "", ""]);
     Expect.equals("foobarabc", bf.toString());
-
-    Expect.equals(bf, bf.addAll(["foo"]));
   }
 
   static testClear() {
     StringBuffer bf = new StringBuffer("");
     bf.add("foo");
     bf.clear();
     Expect.equals("", bf.toString());
     Expect.equals(0, bf.length);
 
     bf.add("bar");
     Expect.equals("bar", bf.toString());
     Expect.equals(3, bf.length);
     bf.clear();
     Expect.equals("", bf.toString());
     Expect.equals(0, bf.length);
-
-    Expect.equals(bf, bf.clear());
   }
 
   static testToString() {
     StringBuffer bf = new StringBuffer("");
     Expect.equals("", bf.toString());
 
     bf = new StringBuffer("foo");
     Expect.equals("foo", bf.toString());
 
     bf = new StringBuffer("foo");
     bf.add("bar");
     Expect.equals("foobar", bf.toString());
   }
 
   static testChaining() {
     StringBuffer bf = new StringBuffer("");
     StringBuffer bf2 = new StringBuffer("");
     bf2.add("bf2");
-    bf.add("foo")
-      .add("bar")
-      .add(bf2)
-      .add(bf2)
-      .add("toto");
+    bf..add("foo")
+      ..add("bar")
+      ..add(bf2)
+      ..add(bf2)
+      ..add("toto");
     Expect.equals("foobarbf2bf2toto", bf.toString());
   }
 
   static testMain() {
     testToString();
     testConstructor();
     testLength();
     testIsEmpty();
     testAdd();
     testAddAll();
     testClear();
     testChaining();
   }
 }
 
 main() {
   StringBufferTest.testMain();
 }