Add flag 'implements' to class, it is set anytime someone implements this class. This is a way to r…

runtime/vm/scanner_test.cc

 // 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.
 
 #include "platform/assert.h"
 #include "vm/os.h"
 #include "vm/scanner.h"
 #include "vm/token.h"
 #include "vm/unit_test.h"
 
@@ skipping 320 matching lines @@
   CheckKind(tokens, 7, Token::kINTEGER);
   CheckKind(tokens, 8, Token::kEOS);
 }
 
 
 void ScanLargeText() {
   const char* dart_source =
       "// This source is not meant to be valid Dart code. The text is used to"
       "// test the Dart scanner."
       ""
-      "// Cartesian point implemetation."
+      "// Cartesian point implementation."
       "class Point {"
       ""
       "  // Constructor"
       "  Point(Number x, Number y) : x(x), y(y) { }"
       ""
       "  // Addition for points."
       "  Point operator +(Point other) {"
       "    return new Point(x + other.x, y + other.y);"
       "  }"
       ""
@@ skipping 88 matching lines @@
   RawString();
   MultilineString();
   EmptyString();
   EmptyMultilineString();
   NumberLiteral();
   InvalidText();
   FindLineTest();
 }
 
 }  // namespace dart