[fsp] Add support for creating directories.

chrome/browser/chromeos/file_system_provider/fake_provided_file_system.cc

Index: chrome/browser/chromeos/file_system_provider/fake_provided_file_system.cc
diff --git a/chrome/browser/chromeos/file_system_provider/fake_provided_file_system.cc b/chrome/browser/chromeos/file_system_provider/fake_provided_file_system.cc
index 4de97247f0d36f18924cb2ac050e23fc194e66c1..e1790c2374428de5d9ba1930f479676a2fe344ae 100644
--- a/chrome/browser/chromeos/file_system_provider/fake_provided_file_system.cc
+++ b/chrome/browser/chromeos/file_system_provider/fake_provided_file_system.cc
@@ -228,6 +228,15 @@ void FakeProvidedFileSystem::ReadFile(
   }
 }
 
+void FakeProvidedFileSystem::CreateDirectory(
+    const base::FilePath& directory_path,
+    bool exclusive,
+    bool recursive,
+    const fileapi::AsyncFileUtil::StatusCallback& callback) {
+  base::MessageLoopProxy::current()->PostTask(
+      FROM_HERE, base::Bind(callback, base::File::FILE_OK));
+}
+
 const ProvidedFileSystemInfo& FakeProvidedFileSystem::GetFileSystemInfo()
     const {
   return file_system_info_;