Add character encoding to Font Settings Extension API.

chrome/test/data/extensions/api_test/font_settings/test.js

 // 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.
 
 // Font settings API test
 // Run with browser_tests --gtest_filter=ExtensionApiTest.FontSettings
 
 var fs = chrome.experimental.fontSettings;
 
 function expect(expected, message) {
@@ skipping 112 matching lines @@
         pixelSize: pixelSize,
         levelOfControl: 'controlled_by_this_extension'
       });
     });
 
     fs.setMinimumFontSize({
       pixelSize: pixelSize
     }, chrome.test.callbackPass());
   },
 
+  function setDefaultCharacterSet() {
+    var charset = 'GBK';
+    chrome.test.listenOnce(fs.onDefaultCharacterSetChanged, function(details) {
+      chrome.test.assertEq(details, {
+        charset: charset,
+        levelOfControl: 'controlled_by_this_extension'
+      });
+    });
+
+    fs.setDefaultCharacterSet({
+      charset: charset
+    }, chrome.test.callbackPass());
+  },
+
   function getDefaultFontSize() {
     var expected = 22;
     var message = 'Setting for default font size should be ' + expected;
     fs.getDefaultFontSize({}, expect({pixelSize: expected}, message));
   },
 
   function getDefaultFontSizeOmitDetails() {
     var expected = 22;
     var message = 'Setting for default font size should be ' + expected;
     fs.getDefaultFontSize(expect({pixelSize: expected}, message));
   },
 
   function getDefaultFixedFontSize() {
     var expected = 42;
     var message = 'Setting for default fixed font size should be ' + expected;
     fs.getDefaultFixedFontSize({}, expect({pixelSize: expected}, message));
   },
 
   function getMinimumFontSize() {
     var expected = 7;
     var message = 'Setting for minimum font size should be ' + expected;
     fs.getMinimumFontSize({}, expect({pixelSize: expected}, message));
-  }
+  },
+
+  function getDefaultCharacterSet() {
+    var expected = 'GBK';
+    var message = 'Setting for default character set should be ' + expected;
+    fs.getDefaultCharacterSet(expect({charset: expected}, message));
+  },
 ]);