Delete the extensions i18n message map when extension unload is received.

chrome/browser/extensions/api/i18n/i18n_apitest.cc

 // Copyright (c) 2012 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 "base/file_util.h"
+#include "base/files/file_path.h"
+#include "base/utf_string_conversions.h"
 #include "chrome/browser/extensions/extension_apitest.h"
+#include "chrome/browser/ui/browser.h"
+#include "chrome/common/extensions/extension.h"
+#include "chrome/test/base/ui_test_utils.h"
+#include "net/test/test_server.h"
 
 IN_PROC_BROWSER_TEST_F(ExtensionApiTest, I18N) {
   ASSERT_TRUE(StartTestServer());
   ASSERT_TRUE(RunExtensionTest("i18n")) << message_;
 }
+
+IN_PROC_BROWSER_TEST_F(ExtensionApiTest, I18NUpdate) {
+  ASSERT_TRUE(StartTestServer());
+  // Create an Extension whose messages.json file will be updated.
+  base::FilePath extension_dir;
+  file_util::CreateNewTempDirectory(base::FilePath::StringType(),

[Yoyo Zhou, 2013/03/08 22:17:50]

Use ScopedTempDir so your temp directory is deleted at the end of the test.

[Patrick Riordan, 2013/03/11 17:32:42]

Done.

+      &extension_dir);
+  file_util::CopyFile(
+      test_data_dir_.AppendASCII("i18nUpdate")
+                    .AppendASCII("manifest.json"),
+      extension_dir.AppendASCII("manifest.json"));
+  file_util::CopyFile(
+      test_data_dir_.AppendASCII("i18nUpdate")
+                    .AppendASCII("contentscript.js"),
+      extension_dir.AppendASCII("contentscript.js"));
+  file_util::CopyDirectory(
+      test_data_dir_.AppendASCII("i18nUpdate")
+                    .AppendASCII("_locales"),
+      extension_dir.AppendASCII("_locales"),
+      true);
+
+  const extensions::Extension* extension = LoadExtension(extension_dir);
+
+  ResultCatcher catcher;
+
+  // Test that the messages.json file is loaded and the i18n message is loaded.
+  ui_test_utils::NavigateToURL(
+      browser(), test_server()->GetURL("file/extensions/test_file.html"));
+  EXPECT_TRUE(catcher.GetNextResult());
+
+  string16 title;
+  ui_test_utils::GetCurrentTabTitle(browser(), &title);
+  EXPECT_EQ(std::string("FIRSTMESSAGE"), UTF16ToUTF8(title));
+
+  // Change messages.json file and reload extension.
+  file_util::CopyFile(
+      test_data_dir_.AppendASCII("i18nUpdate")
+                    .AppendASCII("messages2.json"),
+      extension_dir.AppendASCII("_locales/en/messages.json"));
+  ReloadExtension(extension->id());
+
+  // Check that the i18n message is also changed.
+  ui_test_utils::NavigateToURL(
+      browser(), test_server()->GetURL("file/extensions/test_file.html"));
+  EXPECT_TRUE(catcher.GetNextResult());
+
+  ui_test_utils::GetCurrentTabTitle(browser(), &title);
+  EXPECT_EQ(std::string("SECONDMESSAGE"), UTF16ToUTF8(title));
+}