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

runtime/lib/string_base.dart

 // 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.
 
 /**
  * [_StringBase] contains common methods used by concrete String
  * implementations, e.g., _OneByteString.
  */
 class _StringBase {
 
@@ skipping 201 matching lines @@
       throw new ArgumentError("${pattern} is not a Pattern");
     }
     if (replacement is! String) {
       throw new ArgumentError("${replacement} is not a String");
     }
     StringBuffer buffer = new StringBuffer();
     int startIndex = 0;
     Iterator iterator = pattern.allMatches(this).iterator();
     if (iterator.hasNext) {
       Match match = iterator.next();
-      buffer.add(this.substring(startIndex, match.start)).add(replacement);
+      buffer..add(this.substring(startIndex, match.start))
+            ..add(replacement);
       startIndex = match.end;
     }
-    return buffer.add(this.substring(startIndex)).toString();
+    return (buffer..add(this.substring(startIndex))).toString();
   }
 
   String replaceAll(Pattern pattern, String replacement) {
     if (pattern is! Pattern) {
       throw new ArgumentError("${pattern} is not a Pattern");
     }
     if (replacement is! String) {
       throw new ArgumentError("${replacement} is not a String");
     }
     StringBuffer buffer = new StringBuffer();
     int startIndex = 0;
     for (Match match in pattern.allMatches(this)) {
-      buffer.add(this.substring(startIndex, match.start)).add(replacement);
+      buffer..add(this.substring(startIndex, match.start))
+            ..add(replacement);
       startIndex = match.end;
     }
-    return buffer.add(this.substring(startIndex)).toString();
+    return (buffer..add(this.substring(startIndex))).toString();
   }
 
   /**
    * Convert all objects in [values] to strings and concat them
    * into a result string.
    */
   static String _interpolate(List values) {
     int numValues = values.length;
     var stringList = new List(numValues);
     for (int i = 0; i < numValues; i++) {
@@ skipping 256 matching lines @@
     for (int g in groups) {
       result.add(group(g));
     }
     return result;
   }
 
   final int start;
   final String str;
   final String pattern;
 }