Move computeType to TypedElement and TypeDeclarationElement.

pkg/compiler/lib/src/native/behavior.dart

Index: pkg/compiler/lib/src/native/behavior.dart
diff --git a/pkg/compiler/lib/src/native/behavior.dart b/pkg/compiler/lib/src/native/behavior.dart
index 3fb1c4bf5c3680fd7e3090429226edbb50a86864..edbefd1f85dd32252c5c02e0f556a59cfc1da233 100644
--- a/pkg/compiler/lib/src/native/behavior.dart
+++ b/pkg/compiler/lib/src/native/behavior.dart
@@ -631,7 +631,7 @@ class NativeBehavior {
     return behavior;
   }
 
-  static NativeBehavior ofFieldLoad(Element field, Compiler compiler) {
+  static NativeBehavior ofFieldLoad(MemberElement field, Compiler compiler) {
     DartType type = field.computeType(compiler);
     var behavior = new NativeBehavior();
     behavior.typesReturned.add(type);
@@ -642,7 +642,7 @@ class NativeBehavior {
     return behavior;
   }
 
-  static NativeBehavior ofFieldStore(Element field, Compiler compiler) {
+  static NativeBehavior ofFieldStore(MemberElement field, Compiler compiler) {
     DartType type = field.computeType(compiler);
     var behavior = new NativeBehavior();
     behavior._escape(type, compiler);