Add Worker support for FileSystem API.

chrome/worker/worker_webkitclient_impl.cc

Index: chrome/worker/worker_webkitclient_impl.cc
diff --git a/chrome/worker/worker_webkitclient_impl.cc b/chrome/worker/worker_webkitclient_impl.cc
index b09ca7b79d0f610b61be03db89fd68249ea46f45..048bda001a766e68643c4f44c0d65dead10fd154 100644
--- a/chrome/worker/worker_webkitclient_impl.cc
+++ b/chrome/worker/worker_webkitclient_impl.cc
@@ -17,6 +17,7 @@
 
 using WebKit::WebBlobRegistry;
 using WebKit::WebClipboard;
+using WebKit::WebFileSystem;
 using WebKit::WebKitClient;
 using WebKit::WebMessagePortChannel;
 using WebKit::WebMimeRegistry;
@@ -35,6 +36,12 @@ WebMimeRegistry* WorkerWebKitClientImpl::mimeRegistry() {
   return this;
 }
 
+WebKit::WebFileSystem* WorkerWebKitClientImpl::fileSystem() {
+  if (!web_file_system_.get())
+    web_file_system_.reset(new WebFileSystemImpl());
+  return web_file_system_.get();
+}
+
 WebKit::WebFileUtilities* WorkerWebKitClientImpl::fileUtilities() {
   return &file_utilities_;
 }