Update dart:chrome to include fileSystem, and update summary docs.

sdk/lib/chrome/dart2js/chrome_dart2js.dart

Index: sdk/lib/chrome/dart2js/chrome_dart2js.dart
diff --git a/sdk/lib/chrome/dart2js/chrome_dart2js.dart b/sdk/lib/chrome/dart2js/chrome_dart2js.dart
index 0bca60212b601ccaf321c75cdb0b7aa3b601df5a..77338a8c3068424d42ccabf25d5544c2669080ba 100644
--- a/sdk/lib/chrome/dart2js/chrome_dart2js.dart
+++ b/sdk/lib/chrome/dart2js/chrome_dart2js.dart
@@ -1,10 +1,10 @@
-/// Native wrappers for the Chrome Packaged App APIs.
+/// Native wrappers for the Chrome packaged app APIs.
 ///
-/// These functions allow direct access to the Packaged App APIs, allowing
-/// Chrome Packaged Apps to be written using Dart.
+/// These functions allow direct access to the chrome.* APIs, allowing
+/// Chrome packaged apps to be written using Dart.
 ///
-/// For more information on these APIs, see the Chrome.* APIs Documentation:
-///   http://developer.chrome.com/extensions/api_index.html
+/// For more information on these APIs, see the
+/// [chrome.* API documentation](http://developer.chrome.com/apps/api_index.html).
 library chrome;
 
 import 'dart:_foreign_helper' show JS;
@@ -363,6 +363,7 @@ class API_Chrome {
    * Members
    */
   API_ChromeApp app;
+  API_file_system fileSystem;
 
   /*
    * Constructor
@@ -376,6 +377,11 @@ class API_Chrome {
     if (app_object == null)
       throw new UnsupportedError('Not supported by current browser.');
     app = new API_ChromeApp(app_object);
+
+    var file_system_object = JS('', '#.fileSystem', this._jsObject);
+    if (file_system_object == null)
+      throw new UnsupportedError('Not supported by current browser.');
+    fileSystem = new API_file_system(file_system_object);
   }
 }