dart2js: add initial support for lookup-maps

pkg/compiler/lib/src/js_backend/custom_elements_analysis.dart

 // Copyright (c) 2013, 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.
 
 part of js_backend;
 
 /**
  * Support for Custom Elements.
  *
  * The support for custom elements the compiler builds a table that maps the
@@ skipping 151 matching lines @@
         Iterable<Element> escapingConstructors =
             computeEscapingConstructors(classElement);
         escapingConstructors.forEach(enqueuer.registerStaticUse);
         escapingConstructors
             .forEach(compiler.globalDependencies.registerDependency);
         // Force the generaton of the type constant that is the key to an entry
         // in the generated table.
         ConstantValue constant = makeTypeConstant(classElement);
         backend.registerCompileTimeConstant(
             constant, compiler.globalDependencies);
-        backend.constants.addCompileTimeConstantForEmission(constant);
       }
     }
     activeClasses.addAll(newActiveClasses);
     instantiatedClasses.removeAll(newActiveClasses);
   }
 
   TypeConstantValue makeTypeConstant(ClassElement element) {
     DartType elementType = element.rawType;
     return backend.constantSystem.createType(compiler, elementType);
   }
@@ skipping 15 matching lines @@
           result.add(member);
         }
       }
     }
     classElement.forEachMember(selectGenerativeConstructors,
         includeBackendMembers: false,
         includeSuperAndInjectedMembers: false);
     return result;
   }
 }