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

chrome/browser/chromeos/file_system_provider/throttled_file_system.cc

Index: chrome/browser/chromeos/file_system_provider/throttled_file_system.cc
diff --git a/chrome/browser/chromeos/file_system_provider/throttled_file_system.cc b/chrome/browser/chromeos/file_system_provider/throttled_file_system.cc
index b0d018fff3247f389768598dddec66e1f102aac4..6679e37dca0f56ee7109b8c3045c448c1a320703 100644
--- a/chrome/browser/chromeos/file_system_provider/throttled_file_system.cc
+++ b/chrome/browser/chromeos/file_system_provider/throttled_file_system.cc
@@ -183,6 +183,11 @@ void ThrottledFileSystem::Notify(
                               changes.Pass(), tag, callback);
 }
 
+void ThrottledFileSystem::Configure(
+    const storage::AsyncFileUtil::StatusCallback& callback) {
+  return file_system_->Configure(callback);
+}
+
 base::WeakPtr<ProvidedFileSystemInterface> ThrottledFileSystem::GetWeakPtr() {
   return weak_ptr_factory_.GetWeakPtr();
 }