Add events for configuring and adding new providers to FSP API.

chrome/browser/chromeos/file_system_provider/fake_provided_file_system.h

Index: chrome/browser/chromeos/file_system_provider/fake_provided_file_system.h
diff --git a/chrome/browser/chromeos/file_system_provider/fake_provided_file_system.h b/chrome/browser/chromeos/file_system_provider/fake_provided_file_system.h
index 7e4021e75c981eb45a4be508a81d888f3beb6a28..197a439f0676bdc35c5b01267421c8e3aa534c51 100644
--- a/chrome/browser/chromeos/file_system_provider/fake_provided_file_system.h
+++ b/chrome/browser/chromeos/file_system_provider/fake_provided_file_system.h
@@ -154,6 +154,8 @@ class FakeProvidedFileSystem : public ProvidedFileSystemInterface {
               scoped_ptr<ProvidedFileSystemObserver::Changes> changes,
               const std::string& tag,
               const storage::AsyncFileUtil::StatusCallback& callback) override;
+  void Configure(
+      const storage::AsyncFileUtil::StatusCallback& callback) override;
   base::WeakPtr<ProvidedFileSystemInterface> GetWeakPtr() override;
 
   // Factory callback, to be used in Service::SetFileSystemFactory(). The