Fix warnings in dart2js.

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

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart2js;
 
 typedef ItemCompilationContext ItemCompilationContextCreator();
 
 class EnqueueTask extends CompilerTask {
   final ResolutionEnqueuer resolution;
@@ skipping 200 matching lines @@
         enableNoSuchMethod(member);
       }
       if (member.name == Compiler.CALL_OPERATOR_NAME &&
           !cls.typeVariables.isEmpty) {
         registerGenericCallMethod(member, compiler.globalDependencies);
       }
       // If there is a property access with the same name as a method we
       // 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.
       Link<Element> members = instanceFunctionsByName.putIfAbsent(
           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;
       }
     }
 
     // The element is not yet used. Add it to the list of instance
     // members to still be processed.
     Link<Element> members = instanceMembersByName.putIfAbsent(
         memberName, () => const Link<Element>());
     instanceMembersByName[memberName] = members.prepend(member);
   }
 
@@ skipping 487 matching lines @@
     }
     CodegenWorkItem workItem = new CodegenWorkItem(
         element, itemCompilationContextCreator());
     queue.add(workItem);
   }
 
   void _logSpecificSummary(log(message)) {
     log('Compiled ${generatedCode.length} methods.');
   }
 }