[ew] Add basic classes.

chrome/browser/chromeos/fileapi/file_system_backend.cc

Index: chrome/browser/chromeos/fileapi/file_system_backend.cc
diff --git a/chrome/browser/chromeos/fileapi/file_system_backend.cc b/chrome/browser/chromeos/fileapi/file_system_backend.cc
index fc7fab68d1ae76e63c672ffcc891d736c3bdf786..1e709b6c393d951af3c09fbf34b837b44ae9691b 100644
--- a/chrome/browser/chromeos/fileapi/file_system_backend.cc
+++ b/chrome/browser/chromeos/fileapi/file_system_backend.cc
@@ -248,6 +248,11 @@ fileapi::AsyncFileUtil* FileSystemBackend::GetAsyncFileUtil(
   return NULL;
 }
 
+fileapi::WatcherManager* FileSystemBackend::GetWatcherManager(
+    fileapi::FileSystemType type) {
+  return NULL;
+}
+
 fileapi::CopyOrMoveFileValidatorFactory*
 FileSystemBackend::GetCopyOrMoveFileValidatorFactory(
     fileapi::FileSystemType type, base::File::Error* error_code) {