[app_installer] Refactor and add app_installer_unittests target.

chrome/app_installer/win/app_installer_util_unittest.cc

+// Copyright 2014 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/app_installer/win/app_installer_util.h"
+
+#include <map>
+#include <string>
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace app_installer {
+
+TEST(AppInstallerUtilTest, ParseTag) {
+  std::map<std::string, std::string> parsed_pairs;
+
+  parsed_pairs.clear();
+  EXPECT_TRUE(ParseTag("key1=value1&key2=value2", &parsed_pairs));
+  EXPECT_EQ(2, parsed_pairs.size());
+  EXPECT_EQ("value1", parsed_pairs["key1"]);
+  EXPECT_EQ("value2", parsed_pairs["key2"]);
+
+  parsed_pairs.clear();
+  EXPECT_FALSE(ParseTag("a&b", &parsed_pairs));
+
+  parsed_pairs.clear();
+  EXPECT_FALSE(ParseTag("#=a", &parsed_pairs));
+
+  parsed_pairs.clear();
+  EXPECT_FALSE(ParseTag("a=\01", &parsed_pairs));
+}
+
+}  // namespace app_installer