Reapply 'Add runtimeType() to Object which returns canonicalized instances of Type'.

lib/compiler/implementation/compiler.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.
 
 
 /**
  * If true, print a warning for each method that was resolved, but not
  * compiled.
  */
 const bool REPORT_EXCESS_RESOLUTION = false;
@@ skipping 147 matching lines @@
   closureMapping.ClosureTask closureToClassMapper;
   TypeCheckerTask checker;
   ti.TypesTask typesTask;
   Backend backend;
   ConstantHandler constantHandler;
   EnqueueTask enqueuer;
 
   static const SourceString MAIN = const SourceString('main');
   static const SourceString CALL_OPERATOR_NAME = const SourceString('call');
   static const SourceString NO_SUCH_METHOD = const SourceString('noSuchMethod');
+  static const SourceString RUNTIME_TYPE = const SourceString('runtimeType');
   static const SourceString START_ROOT_ISOLATE =
       const SourceString('startRootIsolate');
   bool enabledNoSuchMethod = false;
+  bool enabledRuntimeType = false;
 
   Stopwatch progress;
 
   static const int PHASE_SCANNING = 0;
   static const int PHASE_RESOLVING = 1;
   static const int PHASE_COMPILING = 2;
   static const int PHASE_RECOMPILING = 3;
   int phase;
 
   bool compilationFailed = false;
@@ skipping 760 matching lines @@
     final endOffset = end.charOffset + end.slowCharCount;
 
     // [begin] and [end] might be the same for the same empty token. This
     // happens for instance when scanning '$$'.
     assert(endOffset >= beginOffset);
     return f(beginOffset, endOffset);
   }
 
   String toString() => 'SourceSpan($uri, $begin, $end)';
 }