[VS Addin] Add visual studio 2012 support

visual_studio/NativeClientVSAddIn/UnitTests/CompileParallelTest.cs

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 using System;
 using System.Text;
 using System.Collections.Generic;
 using EnvDTE;
 using EnvDTE80;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using Microsoft.VisualStudio.VCProjectEngine;
 using NaCl.Build.CPPTasks;
 using NativeClientVSAddIn;
 
 namespace UnitTests
 {
     [TestClass]
     public class CompileParallelTest : BaseCompileTest
     {
         private static string SolutionBaseName_ = "CompileParallelTest";
 
         [ClassInitialize]
-        public new static void ClassSetUp(TestContext testContext)
+        public static void ClassSetUp(TestContext testContext)
         {
             BaseCompileTest.ClassSetUp(testContext, SolutionBaseName_);
         }
 
         /// <summary>
         /// This is run after each test to clean up things created in TestSetup().
         /// </summary>
         [TestCleanup]
         public void ClassTearDown()
         {
             TestUtilities.CleanUpVisualStudioInstance(dte_);
         }
 
         /// <summary>
         /// Test that parallel compilation works.
         /// </summary>
         [TestMethod]
         public void CheckParallelCompile()
         {
             string platform = Strings.NaCl64PlatformName;
             dte_.Solution.Open(SolutionName_);
             Project project = dte_.Solution.Projects.Item(TestUtilities.NaClProjectUniqueName);
 
             // Add property sheet that enables multiprocessing
             VCConfiguration config;
-            IVCRulePropertyStorage rule;
             config = TestUtilities.GetVCConfiguration(project, "Debug", platform);
             config.AddPropertySheet("multiprocess.props");
             config = TestUtilities.GetVCConfiguration(project, "Release", platform);
             config.AddPropertySheet("multiprocess.props");
 
             // Add a second file
             project.ProjectItems.AddFromFile("test_file.cpp");
 
             dte_.Solution.Close(true);
 
             CheckCompile(platform, false);
         }
     }
 }