Change Enqueuer to use Entity instead of Element.

tests/compiler/dart2js/memory_compiler.dart

 // Copyright (c) 2016, 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.
 
 library dart2js.test.memory_compiler;
 
 import 'dart:async';
 
 import 'package:compiler/compiler.dart' show DiagnosticHandler;
 import 'package:compiler/compiler_new.dart'
@@ skipping 165 matching lines @@
       }
     });
     // TODO(johnniwinther): Assert that no libraries are loaded lazily from
     // this call.
     compiler.onLibrariesLoaded(new MemoryLoadedLibraries(copiedLibraries));
 
     compiler.backend.constantCompilerTask
         .copyConstantValues(cachedCompiler.backend.constantCompilerTask);
 
     Iterable cachedTreeElements =
-        cachedCompiler.enqueuer.resolution.processedElements;
+        cachedCompiler.enqueuer.resolution.processedEntities;
     cachedTreeElements.forEach((element) {
       if (element.library.isPlatformLibrary) {
         compiler.enqueuer.resolution.registerProcessedElement(element);
       }
     });
 
     // One potential problem that can occur when reusing elements is that there
     // is a stale reference to an old compiler object.  By nulling out the old
     // compiler's fields, such stale references are easier to identify.
     cachedCompiler.scanner = null;
@@ skipping 47 matching lines @@
       handler = (Uri uri, int begin, int end, String message, Diagnostic kind) {
         diagnosticHandler(uri, begin, end, message, kind);
         formattingHandler(uri, begin, end, message, kind);
       };
     }
   } else if (diagnosticHandler == null) {
     handler = (Uri uri, int begin, int end, String message, Diagnostic kind) {};
   }
   return handler;
 }