Allow whitelisted prefs to be displayed in ChromeOS in chrome://local-state.

chrome/browser/ui/webui/local_state/local_state_ui_unittest.cc

+// 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/browser/ui/webui/local_state/local_state_ui.h"
+
+#include "base/values.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+TEST(LocalStateUiTest, FilterPrefs) {
+  std::vector<std::string> prefixes = {"foo", "bar", "baz"};
+
+  std::vector<std::string> invalid_pref_keys = {"fo", "ar", "afoo"};
+  std::vector<std::string> valid_pref_keys = {"foo", "foom", "bar.stuff"};
+
+  std::vector<std::string> all_pref_keys = invalid_pref_keys;
+  all_pref_keys.insert(all_pref_keys.end(), valid_pref_keys.begin(),
+                       valid_pref_keys.end());
+
+  base::DictionaryValue prefs;
+  for (const std::string& key : all_pref_keys) {
+    prefs.Set(key, new base::StringValue(key + "_value"));
+  }
+
+  internal::FilterPrefs(prefixes, &prefs);
+
+  for (const std::string& invalid_key : invalid_pref_keys) {
+    std::string value;
+    EXPECT_FALSE(prefs.GetString(invalid_key, &value));
+  }
+
+  for (const std::string& valid_key : valid_pref_keys) {
+    std::string value;
+    EXPECT_TRUE(prefs.GetString(valid_key, &value));
+    EXPECT_EQ(valid_key + "_value", value);
+  }
+}