Reapply "Implement new model for class members." and "Implement new model for interface members."

sdk/lib/_internal/compiler/implementation/elements/modelx.dart

Index: sdk/lib/_internal/compiler/implementation/elements/modelx.dart
diff --git a/sdk/lib/_internal/compiler/implementation/elements/modelx.dart b/sdk/lib/_internal/compiler/implementation/elements/modelx.dart
index eedf6a41b479a27fbbb235374d1807cf5b06d613..3ad8ac19c58b3e70cdd1aa1c5327c8ff5787f1ae 100644
--- a/sdk/lib/_internal/compiler/implementation/elements/modelx.dart
+++ b/sdk/lib/_internal/compiler/implementation/elements/modelx.dart
@@ -1767,6 +1767,7 @@ abstract class BaseClassElementX extends ElementX implements ClassElement {
   int resolutionState;
   bool get isResolved => resolutionState == STATE_DONE;
   bool isProxy = false;
+  bool hasIncompleteHierarchy = false;
 
   // backendMembers are members that have been added by the backend to simplify
   // compilation. They don't have any user-side counter-part.
@@ -1778,6 +1779,9 @@ abstract class BaseClassElementX extends ElementX implements ClassElement {
 
   int get hierarchyDepth => allSupertypesAndSelf.maxDepth;
 
+  Map<Name, Member> classMembers;
+  Map<Name, MemberSignature> interfaceMembers;
+
   BaseClassElementX(String name,
                     Element enclosing,
                     this.id,
@@ -2151,6 +2155,18 @@ abstract class BaseClassElementX extends ElementX implements ClassElement {
   void setNative(String name) {
     nativeTagInfo = name;
   }
+
+  Member lookupClassMember(Name name) => classMembers[name];
+
+  void forEachClassMember(f(Member member)) {
+    classMembers.forEach((_, member) => f(member));
+  }
+
+  MemberSignature lookupInterfaceMember(Name name) => interfaceMembers[name];
+
+  void forEachInterfaceMember(f(MemberSignature member)) {
+    interfaceMembers.forEach((_, member) => f(member));
+  }
 }
 
 abstract class ClassElementX extends BaseClassElementX {