Implement a list tracer phase, that tries to find element types in individual lists.

tests/compiler/dart2js/mock_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.
 
 library mock_compiler;
 
 import "package:expect/expect.dart";
 import 'dart:collection';
 
 import '../../../sdk/lib/_internal/compiler/compiler.dart' as api;
@@ skipping 47 matching lines @@
     var target;
     var receiver;
   }
   class Closure {}
   class Null {}
   class Dynamic_ {}
   class LinkedHashMap {}
   class ConstantMap {}
   class TypeImpl {}
   S() {}
+  throwCyclicInit() {}
   throwExpression(e) {}
   unwrapException(e) {}
   assertHelper(a) {}
   isJsIndexable(a, b) {}
   createRuntimeType(a) {}
   createInvocationMirror(a0, a1, a2, a3, a4, a5) {}
   throwNoSuchMethod(obj, name, arguments, expectedArgumentNames) {}
   throwAbstractClassInstantiationError(className) {}''';
 
 const String FOREIGN_LIBRARY = r'''
@@ skipping 82 matching lines @@
   class bool {}
   class String implements Pattern {}
   class Object {
     operator ==(other) { return true; }
     String toString() { return null; }
     noSuchMethod(im) { throw im; }
   }
   abstract class StackTrace {}
   class Type {}
   class Function {}
-  class List<E> {}
+  class List<E> { List([length]); }
   abstract class Map<K,V> {}
   class DateTime {
     DateTime(year);
     DateTime.utc(year);
   }
   abstract class Pattern {}
   bool identical(Object a, Object b) { return true; }''';
 
 const String DEFAULT_ISOLATE_HELPERLIB = r'''
   class _WorkerBase {}''';
@@ skipping 249 matching lines @@
   }
 }
 
 class MockDeferredLoadTask extends DeferredLoadTask {
   MockDeferredLoadTask(Compiler compiler) : super(compiler);
 
   void registerMainApp(LibraryElement mainApp) {
     // Do nothing.
   }
 }