Fixit: Remove bunch of coverity warnings from chrome/installer/*.

chrome/installer/util/copy_tree_work_item_unittest.cc

Index: chrome/installer/util/copy_tree_work_item_unittest.cc
diff --git a/chrome/installer/util/copy_tree_work_item_unittest.cc b/chrome/installer/util/copy_tree_work_item_unittest.cc
index 70ba378a38d36effd0e482c1c8d1e85c0102fd5c..77b67191f70ef1fbecd38de9c9ec4871931c7a99 100644
--- a/chrome/installer/util/copy_tree_work_item_unittest.cc
+++ b/chrome/installer/util/copy_tree_work_item_unittest.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Copyright (c) 2009 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.
 
@@ -61,7 +61,7 @@ namespace {
     file.close();
   }
 
-  bool IsFileInUse(std::wstring path) {
+  bool IsFileInUse(const std::wstring& path) {
     if (!file_util::PathExists(path))
       return false;