Don't cache subtypes in elements. It causes a memory leak in the Editor.

dart/compiler/java/com/google/dart/compiler/resolver/ClassElement.java

Index: dart/compiler/java/com/google/dart/compiler/resolver/ClassElement.java
diff --git a/dart/compiler/java/com/google/dart/compiler/resolver/ClassElement.java b/dart/compiler/java/com/google/dart/compiler/resolver/ClassElement.java
index 4090d09292c275ccf2216c5979c7596819cec068..657a90d8f0144e2a2ffb161ac51b2780927580ec 100644
--- a/dart/compiler/java/com/google/dart/compiler/resolver/ClassElement.java
+++ b/dart/compiler/java/com/google/dart/compiler/resolver/ClassElement.java
@@ -30,13 +30,6 @@ public interface ClassElement extends EnclosingElement {
 
   List<InterfaceType> getInterfaces();
 
-  /**
-   * Returns the static subtypes of a declared type including itself.  This method should only be
-   * called once all elements have been built.  The results are cached so subtypes added after
-   * building will not be reflected.
-   */
-  Set<InterfaceType> getSubtypes();
-
   List<InterfaceType> getAllSupertypes()
       throws CyclicDeclarationException, DuplicatedInterfaceException;