dart2js: Fix hints in code base.

pkg/compiler/lib/src/resolution/send_resolver.dart

 // Copyright (c) 2015, 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.semantics_visitor;
 
 enum SendStructureKind {
   GET,
   SET,
   INVOKE,
@@ skipping 194 matching lines @@
     SendStructure sendStructure = elements.getSendStructure(node);
     if (sendStructure != null) {
       return sendStructure;
     }
 
     if (elements.isAssert(node)) {
       return internalError(node, "Unexpected assert.");
     }
 
     AssignmentOperator assignmentOperator;
-    UnaryOperator unaryOperator;
     BinaryOperator binaryOperator;
     IncDecOperator incDecOperator;
 
     if (node.isOperator) {
       String operatorText = node.selector.asOperator().source;
       if (operatorText == 'is') {
         return internalError(node, "Unexpected is test.");
       } else if (operatorText == 'as') {
         return internalError(node, "Unexpected as cast.");
       } else if (operatorText == '&&') {
@@ skipping 757 matching lines @@
       return internalError(node, "Unexpected variable $element.");
     }
     if (element.isConst) {
       ConstantExpression constant = elements.getConstant(element.initializer);
       return new ConstantVariableStructure(kind, node, element, constant);
     } else {
       return new NonConstantVariableStructure(kind, node, element);
     }
   }
 }