Simplify WorkItemListTest.

chrome/installer/util/work_item_mocks.cc

Index: chrome/installer/util/work_item_mocks.cc
diff --git a/chrome/installer/util/work_item_mocks.cc b/chrome/installer/util/work_item_mocks.cc
new file mode 100644
index 0000000000000000000000000000000000000000..44ed44288bbaed388dc3573d86a23b3d014c49a4
--- /dev/null
+++ b/chrome/installer/util/work_item_mocks.cc
@@ -0,0 +1,11 @@
+// Copyright 2016 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.
+
+#include "chrome/installer/util/work_item_mocks.h"
+
+MockWorkItem::MockWorkItem() = default;
+MockWorkItem::~MockWorkItem() = default;
+
+MockCondition::MockCondition() = default;
+MockCondition::~MockCondition() = default;