Introduce typed selectors to do better tree shaking based on calls on 'this'. Getters and setters w…

lib/compiler/implementation/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('../tree/tree.dart');
 #import('../scanner/scannerlib.dart');
 #import('../leg.dart');  // TODO(karlklose): we only need type.
 #import('../util/util.dart');
@@ skipping 828 matching lines @@
   bool implementsInterface(ClassElement intrface) {
     for (Type implementedInterfaceType in allSupertypes) {
       ClassElement implementedInterface = implementedInterfaceType.element;
       if (implementedInterface === intrface) {
         return true;
       }
     }
     return false;
   }
 
+  /**
+   * Returns true if [this] is a subclass of [cls].
+   *
+   * This method is not to be used for checking type hierarchy and
+   * assignments, because it does not take parameterized types into
+   * account.
+   */
+  bool isSubclassOf(ClassElement cls) {
+    for (ClassElement s = this; s != null; s = s.superclass) {
+      if (s === cls) return true;
+    }
+    return false;
+  }
+
   bool isInterface() => false;
   bool isNative() => nativeName != null;
   SourceString nativeName;
 }
 
 class Elements {
   static bool isLocal(Element element) {
     return ((element !== null)
             && !element.isInstanceMember()
             && !isStaticOrTopLevelField(element)
@@ skipping 168 matching lines @@
   final Node node;
   Type bound;
   Type type;
   TypeVariableElement(name, Element enclosing, this.node, this.type,
                       [this.bound])
     : super(name, ElementKind.TYPE_VARIABLE, enclosing);
   Type computeType(compiler) => type;
   Node parseNode(compiler) => node;
   toString() => "${enclosingElement.toString()}.${name.slowToString()}";
 }