Fix warnings in dart2js.

sdk/lib/_internal/compiler/implementation/enqueue.dart

Index: sdk/lib/_internal/compiler/implementation/enqueue.dart
diff --git a/sdk/lib/_internal/compiler/implementation/enqueue.dart b/sdk/lib/_internal/compiler/implementation/enqueue.dart
index 06ed03b2a6b784302df34fa5d4c868ec663d2628..e97f3dcb5d8c2ac65702973503a4aa584f7528c6 100644
--- a/sdk/lib/_internal/compiler/implementation/enqueue.dart
+++ b/sdk/lib/_internal/compiler/implementation/enqueue.dart
@@ -218,7 +218,8 @@ abstract class Enqueuer {
       // need to emit the method.
       if (universe.hasInvokedGetter(member, compiler)) {
         registerClosurizedMember(member, compiler.globalDependencies);
-        return addToWorkList(member);
+        addToWorkList(member);
+        return;
       }
       // Store the member in [instanceFunctionsByName] to catch
       // getters on the function.
@@ -226,20 +227,24 @@ abstract class Enqueuer {
           memberName, () => const Link<Element>());
       instanceFunctionsByName[memberName] = members.prepend(member);
       if (universe.hasInvocation(member, compiler)) {
-        return addToWorkList(member);
+        addToWorkList(member);
+        return;
       }
     } else if (member.kind == ElementKind.GETTER) {
       if (universe.hasInvokedGetter(member, compiler)) {
-        return addToWorkList(member);
+        addToWorkList(member);
+        return;
       }
       // We don't know what selectors the returned closure accepts. If
       // the set contains any selector we have to assume that it matches.
       if (universe.hasInvocation(member, compiler)) {
-        return addToWorkList(member);
+        addToWorkList(member);
+        return;
       }
     } else if (member.kind == ElementKind.SETTER) {
       if (universe.hasInvokedSetter(member, compiler)) {
-        return addToWorkList(member);
+        addToWorkList(member);
+        return;
       }
     }