Use union type parts when check if type is subtype.

compiler/java/com/google/dart/compiler/type/InterfaceTypeUnion.java

Index: compiler/java/com/google/dart/compiler/type/InterfaceTypeUnion.java
diff --git a/compiler/java/com/google/dart/compiler/type/InterfaceTypeUnion.java b/compiler/java/com/google/dart/compiler/type/InterfaceTypeUnion.java
index c3eca3b606ca9b66909949ff3670f4ad4321ae7a..87a6c9cf5e2a238722c6c271a9df50050422bb58 100644
--- a/compiler/java/com/google/dart/compiler/type/InterfaceTypeUnion.java
+++ b/compiler/java/com/google/dart/compiler/type/InterfaceTypeUnion.java
@@ -1,111 +1,17 @@
-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// 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.
 
 package com.google.dart.compiler.type;
 
-import com.google.common.collect.ImmutableList;
-import com.google.dart.compiler.resolver.ClassElement;
-import com.google.dart.compiler.resolver.ClassElementUnion;
-
 import java.util.List;
 
 /**
  * Artificial {@link InterfaceType} which is union of several {@link InterfaceType}s.
  */
-class InterfaceTypeUnion implements InterfaceType {
-  
-  private final List<InterfaceType> types;
-  private final ClassElement element;
-
-  public InterfaceTypeUnion(List<InterfaceType> types) {
-    this.types = types;
-    this.element = new ClassElementUnion(this, types);
-  }
-  
-  @Override
-  public boolean equals(Object obj) {
-    if (obj instanceof InterfaceTypeUnion) {
-      InterfaceTypeUnion other = (InterfaceTypeUnion) obj;
-      return getElement().equals(other.getElement());
-    }
-    return false;
-  }
-
-  @Override
-  public int hashCode() {
-    int hashCode = 31;
-    hashCode += getElement().hashCode();
-    hashCode += 31 * hashCode + getArguments().hashCode();
-    return hashCode;
-  }
-
-  @Override
-  public String toString() {
-    return types.toString();
-  }
-  
-  @Override
-  public TypeKind getKind() {
-    return TypeKind.INTERFACE;
-  }
-
-  @Override
-  public TypeQuality getQuality() {
-    return TypeQuality.EXACT;
-  }
-
-  @Override
-  public InterfaceType subst(List<Type> arguments, List<Type> parameters) {
-    return null;
-  }
-
-  @Override
-  public ClassElement getElement() {
-    return element;
-  }
-
-  @Override
-  public List<Type> getArguments() {
-    return ImmutableList.of();
-  }
-
-  @Override
-  public boolean isRaw() {
-    return true;
-  }
-
-  @Override
-  public boolean hasDynamicTypeArgs() {
-    return false;
-  }
-
-  @Override
-  public InterfaceType asRawType() {
-    return this;
-  }
-
-  @Override
-  public Member lookupMember(String name) {
-    for (InterfaceType type : types) {
-      Member member = type.lookupMember(name);
-      if (member != null) {
-        return member;
-      }
-    }
-    return null;
-  }
-  
-  @Override
-  public void registerSubClass(ClassElement subClass) {
-  }
-  
-  @Override
-  public void unregisterSubClass(ClassElement subClass) {
-  }
-  
-  @Override
-  public Member lookupSubTypeMember(String name) {
-    return null;
-  }
+public interface InterfaceTypeUnion extends InterfaceType {
+  /**
+   * @return the {@link InterfaceType} making this union.
+   */
+  List<InterfaceType> getTypes();
 }