Add forEachLibraryMember and forEachConstructor to ElementEnvironment

pkg/compiler/lib/src/common_elements.dart

Index: pkg/compiler/lib/src/common_elements.dart
diff --git a/pkg/compiler/lib/src/common_elements.dart b/pkg/compiler/lib/src/common_elements.dart
index 205dbb7a2cee7b83188c3755544bee86a6f561e8..26c72ef6b17313c2d1dd9532830e438c18263c92 100644
--- a/pkg/compiler/lib/src/common_elements.dart
+++ b/pkg/compiler/lib/src/common_elements.dart
@@ -1177,6 +1177,9 @@ abstract class ElementEnvironment {
   ClassEntity lookupClass(LibraryEntity library, String name,
       {bool required: false});
 
+  /// Calls [f] for every top level member in [library].
+  void forEachLibraryMember(LibraryEntity library, void f(MemberEntity member));
+
   /// Lookup the member [name] in [library], fail if the class is missing and
   /// [required].
   MemberEntity lookupLibraryMember(LibraryEntity library, String name,
@@ -1200,6 +1203,10 @@ abstract class ElementEnvironment {
   void forEachClassMember(
       ClassEntity cls, void f(ClassEntity declarer, MemberEntity member));
 
+  /// Calls [f] for every constructor declared in [cls].
+  void forEachConstructor(
+      ClassEntity cls, void f(ConstructorEntity constructor));
+
   /// Returns the superclass of [cls].
   ///
   /// If [skipUnnamedMixinApplications] is `true`, unnamed mixin applications