DriveFileSyncService listens to OnAuthenticated event to recover from unavailable state

chrome/browser/sync_file_system/drive_file_sync_client.cc

Index: chrome/browser/sync_file_system/drive_file_sync_client.cc
diff --git a/chrome/browser/sync_file_system/drive_file_sync_client.cc b/chrome/browser/sync_file_system/drive_file_sync_client.cc
index a192849b9078c6614b7c01ee72ed5e04a9d599a3..f7a52f062db5457f0d4b452657ea5e0680367550 100644
--- a/chrome/browser/sync_file_system/drive_file_sync_client.cc
+++ b/chrome/browser/sync_file_system/drive_file_sync_client.cc
@@ -68,6 +68,7 @@ DriveFileSyncClient::DriveFileSyncClient(Profile* profile) {
       GURL(google_apis::GDataWapiUrlGenerator::kBaseUrlForProduction),
       "" /* custom_user_agent */));
   drive_service_->Initialize(profile);
+  drive_service_->AddObserver(this);
 
   drive_uploader_.reset(new google_apis::DriveUploader(drive_service_.get()));
 }
@@ -86,15 +87,28 @@ DriveFileSyncClient::DriveFileSyncClient(
     scoped_ptr<google_apis::DriveUploaderInterface> drive_uploader) {
   drive_service_ = drive_service.Pass();
   drive_service_->Initialize(profile);
+  drive_service_->AddObserver(this);
 
   drive_uploader_ = drive_uploader.Pass();
 }
 
 DriveFileSyncClient::~DriveFileSyncClient() {
   DCHECK(CalledOnValidThread());
+  drive_service_->RemoveObserver(this);
   drive_service_->CancelAll();
 }
 
+void DriveFileSyncClient::AddObserver(DriveFileSyncClientObserver* observer) {
+  DCHECK(CalledOnValidThread());
+  observers_.AddObserver(observer);
+}
+
+void DriveFileSyncClient::RemoveObserver(
+    DriveFileSyncClientObserver* observer) {
+  DCHECK(CalledOnValidThread());
+  observers_.RemoveObserver(observer);
+}
+
 void DriveFileSyncClient::GetDriveDirectoryForSyncRoot(
     const ResourceIdCallback& callback) {
   DCHECK(CalledOnValidThread());
@@ -356,6 +370,11 @@ void DriveFileSyncClient::DeleteFile(
                             AsWeakPtr(), remote_file_md5, callback)));
 }
 
+void DriveFileSyncClient::OnReadyToPerformOperations() {
+  DCHECK(CalledOnValidThread());
+  FOR_EACH_OBSERVER(DriveFileSyncClientObserver, observers_, OnAuthenticated());
+}
+
 void DriveFileSyncClient::DidGetDocumentFeedData(
     const DocumentFeedCallback& callback,
     google_apis::GDataErrorCode error,