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

chrome/test/data/extensions/api_test/preference/clear/test.html

 <script>
 // Content settings API test
-// Run with browser_tests --gtest_filter=ExtensionApiTest.ContentSettingsClear
+// Run with browser_tests --gtest_filter=ExtensionApiTest.PreferenceClear
 
-var cs = chrome.experimental.contentSettings;
+var pw = chrome.experimental.privacy.websites;
 chrome.test.runTests([
   function getThirdPartyCookiesAllowed() {
-    cs.global.thirdPartyCookiesAllowed.get({}, chrome.test.callbackPass(
+    pw.thirdPartyCookiesAllowed.get({}, chrome.test.callbackPass(
         function(allowed) {
           chrome.test.assertEq(
               allowed,
               {
                 'value': false,
                 'levelOfControl': "controllable_by_this_extension"
               },
               "third-party cookies should be blocked");
         }));
   },
   function setThirdPartyCookiesAllowed() {
-    cs.global.thirdPartyCookiesAllowed.set(
+    pw.thirdPartyCookiesAllowed.set(
         {'value': true},
         chrome.test.callbackPass());
   },
   function clearThirdPartyCookiesAllowed() {
-    cs.global.thirdPartyCookiesAllowed.clear({}, chrome.test.callbackPass());
+    pw.thirdPartyCookiesAllowed.clear({}, chrome.test.callbackPass());
   },
   function getThirdPartyCookiesAllowed2() {
-    cs.global.thirdPartyCookiesAllowed.get({}, chrome.test.callbackPass(
+    pw.thirdPartyCookiesAllowed.get({}, chrome.test.callbackPass(
         function(allowed) {
           chrome.test.assertEq(
               allowed,
               {
                 'value': false,
                 'levelOfControl': "controllable_by_this_extension"
               },
               "third-party cookies should be blocked");
         }));
   }
 ]);
 </script>