Further reduce use of Element in codegen.

pkg/compiler/lib/src/elements/elements.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 elements;
 
 import '../common.dart';
 import '../common/resolution.dart' show Resolution;
 import '../compiler.dart' show Compiler;
 import '../constants/constructors.dart';
@@ skipping 658 matching lines @@
     if (identical(op, '<<=')) return '<<';
     if (identical(op, '>>=')) return '>>';
     if (identical(op, '&=')) return '&';
     if (identical(op, '^=')) return '^';
     if (identical(op, '|=')) return '|';
     if (identical(op, '??=')) return '??';
 
     return null;
   }
 
-  static bool isNumberOrStringSupertype(
-      Element element, CommonElements commonElements) {
-    LibraryElement coreLibrary = commonElements.coreLibrary;
-    return (element == coreLibrary.find('Comparable'));
-  }
-
-  static bool isStringOnlySupertype(
-      Element element, CommonElements commonElements) {
-    LibraryElement coreLibrary = commonElements.coreLibrary;
-    return element == coreLibrary.find('Pattern');
-  }
-
-  static bool isListSupertype(Element element, CommonElements commonElements) {
-    LibraryElement coreLibrary = commonElements.coreLibrary;
-    return element == coreLibrary.find('Iterable');
-  }
-
   /// A `compareTo` function that places [Element]s in a consistent order based
   /// on the source code order.
   static int compareByPosition(Element a, Element b) {
     if (identical(a, b)) return 0;
     int r = _compareLibraries(a.library, b.library);
     if (r != 0) return r;
     r = _compareCompilationUnits(a.compilationUnit, b.compilationUnit);
     if (r != 0) return r;
     int offsetA = a.sourceOffset ?? -1;
     int offsetB = b.sourceOffset ?? -1;
@@ skipping 1228 matching lines @@
   /// by a field.
   bool get isDeclaredByField;
 
   /// Returns `true` if this member is abstract.
   bool get isAbstract;
 
   /// If abstract, [implementation] points to the overridden concrete member,
   /// if any. Otherwise [implementation] points to the member itself.
   Member get implementation;
 }