Expose privacy-relevant preferences via Chrome's extension API.

chrome/test/data/extensions/api_test/content_settings/onchange/test.html

-<script>
-// Content settings API test
-// Run with browser_tests --gtest_filter=ExtensionApiTest.ContentSettingsOnChange
-
-// Listen until |event| has fired with all of the values in |expected|.
-function listenUntil(event, expected) {
-  var done = chrome.test.listenForever(event, function(value) {
-    for (var i = 0; i < expected.length; i++) {
-      if (chrome.test.checkDeepEq(expected[i], value)) {
-        expected.splice(i, 1);
-        if (expected.length == 0)
-          done();
-        return;
-      }
-    }
-    chrome.test.fail("Unexpected event: " + JSON.stringify(value));
-  });
-}
-
-var cs = chrome.experimental.contentSettings;
-chrome.test.runTests([
-  function changeDefault() {
-    // Changing the regular settings when no incognito-specific settings are
-    // defined should fire two events.
-    listenUntil(cs.global.thirdPartyCookiesAllowed.onChange, [{
-      'value': false,
-      'levelOfControl': 'controlled_by_this_extension'
-    },
-    {
-      'value': false,
-      'incognitoSpecific': false,
-      'levelOfControl': 'controlled_by_this_extension'
-    }]);
-    cs.global.thirdPartyCookiesAllowed.set({
-      'value':false
-    }, chrome.test.callbackPass());
-  },
-  function changeIncognitoOnly() {
-    listenUntil(cs.global.thirdPartyCookiesAllowed.onChange, [{
-      'value': true,
-      'incognitoSpecific': true,
-      'levelOfControl': 'controlled_by_this_extension'
-    }]);
-    cs.global.thirdPartyCookiesAllowed.set({
-      'value': true,
-      'scope': 'incognito_persistent'
-    }, chrome.test.callbackPass());
-  },
-  function changeDefaultOnly() {
-    listenUntil(cs.global.thirdPartyCookiesAllowed.onChange, [{
-      'value': true,
-      'levelOfControl': 'controlled_by_this_extension'
-    }]);
-    cs.global.thirdPartyCookiesAllowed.set({
-      'value': true
-    }, chrome.test.callbackPass());
-  },
-  function changeIncognitoOnlyBack() {
-    // Change the incognito setting back to false so that we get an event when
-    // clearing the value.
-    listenUntil(cs.global.thirdPartyCookiesAllowed.onChange, [{
-      'value': false,
-      'incognitoSpecific': true,
-      'levelOfControl': 'controlled_by_this_extension'
-    }]);
-    cs.global.thirdPartyCookiesAllowed.set({
-      'value': false,
-      'scope': 'incognito_persistent'
-    }, chrome.test.callbackPass());
-  },
-  function clearIncognito() {
-    listenUntil(cs.global.thirdPartyCookiesAllowed.onChange, [{
-      'value': true,
-      'incognitoSpecific': false,
-      'levelOfControl': 'controlled_by_this_extension'
-    }]);
-    cs.global.thirdPartyCookiesAllowed.clear({
-      'scope': 'incognito_persistent'
-    }, chrome.test.callbackPass());
-  },
-  function clearDefault() {
-    listenUntil(cs.global.thirdPartyCookiesAllowed.onChange, [{
-      'value': true,
-      'levelOfControl': 'controllable_by_this_extension'
-    },
-    {
-      'value': true,
-      'incognitoSpecific': false,
-      'levelOfControl': 'controllable_by_this_extension'
-    }]);
-    cs.global.thirdPartyCookiesAllowed.clear({}, chrome.test.callbackPass());
-  }
-]);
-
-</script>