Fix some issues in element serialization.

pkg/compiler/lib/src/elements/modelx.dart

Index: pkg/compiler/lib/src/elements/modelx.dart
diff --git a/pkg/compiler/lib/src/elements/modelx.dart b/pkg/compiler/lib/src/elements/modelx.dart
index b5f8417ddef816d64d54b306adb27dbd8bd7aa63..2e462f4dca7f97f96ff7cc910b4bf3576e9b4060 100644
--- a/pkg/compiler/lib/src/elements/modelx.dart
+++ b/pkg/compiler/lib/src/elements/modelx.dart
@@ -109,12 +109,6 @@ abstract class ElementX extends Element with ElementCommon {
     return enclosingElement != null && enclosingElement.isCompilationUnit;
   }
 
-  bool get isAssignable {
-    if (isFinal || isConst) return false;
-    if (isFunction || isConstructor) return false;
-    return true;
-  }
-
   Token get position => null;
 
   SourceSpan get sourcePosition {
@@ -177,19 +171,6 @@ abstract class ElementX extends Element with ElementCommon {
     return null;
   }
 
-  Element get outermostEnclosingMemberOrTopLevel {
-    // TODO(lrn): Why is this called "Outermost"?
-    // TODO(johnniwinther): Clean up this method: This method does not return
-    // the outermost for elements in closure classses, but some call-sites rely
-    // on that behavior.
-    for (Element e = this; e != null; e = e.enclosingElement) {
-      if (e.isClassMember || e.isTopLevel) {
-        return e;
-      }
-    }
-    return null;
-  }
-
   /**
    * Creates the scope for this element.
    */