drive: Pass through AboutResouce from server among callbacks in ChangeListLoader.

chrome/browser/chromeos/drive/change_list_loader.cc

Index: chrome/browser/chromeos/drive/change_list_loader.cc
diff --git a/chrome/browser/chromeos/drive/change_list_loader.cc b/chrome/browser/chromeos/drive/change_list_loader.cc
index 93b24c01bb96c486374174dcf7481c2313c4642d..cb0354604775cca02665274131886bb9e7d3857c 100644
--- a/chrome/browser/chromeos/drive/change_list_loader.cc
+++ b/chrome/browser/chromeos/drive/change_list_loader.cc
@@ -264,30 +264,28 @@ void ChangeListLoader::LoadFromServerIfNeededAfterGetAbout(
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DCHECK(!callback.is_null());
   DCHECK(refreshing_);
-
-  int64 remote_changestamp = 0;
-  if (util::GDataToDriveFileError(status) == DRIVE_FILE_OK) {
-    DCHECK(about_resource);
-    remote_changestamp = about_resource->largest_change_id();
-  }
+  DCHECK_EQ(util::GDataToDriveFileError(status) == DRIVE_FILE_OK,
+            about_resource.get() != NULL);
 
   resource_metadata_->GetLargestChangestamp(
       base::Bind(&ChangeListLoader::CompareChangestampsAndLoadIfNeeded,
                  weak_ptr_factory_.GetWeakPtr(),
                  directory_fetch_info,
                  callback,
-                 remote_changestamp));
+                 base::Passed(&about_resource)));
 }
 
 void ChangeListLoader::CompareChangestampsAndLoadIfNeeded(
     const DirectoryFetchInfo& directory_fetch_info,
     const FileOperationCallback& callback,
-    int64 remote_changestamp,
+    scoped_ptr<google_apis::AboutResource> about_resource,
     int64 local_changestamp) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DCHECK(!callback.is_null());
   DCHECK(refreshing_);
 
+  int64 remote_changestamp =
+      about_resource ? about_resource->largest_change_id() : 0;
   if (remote_changestamp > 0 && local_changestamp >= remote_changestamp) {
     if (local_changestamp > remote_changestamp) {
       LOG(WARNING) << "Cached client feed is fresher than server, client = "
@@ -302,16 +300,22 @@ void ChangeListLoader::CompareChangestampsAndLoadIfNeeded(
   }
 
   int64 start_changestamp = local_changestamp > 0 ? local_changestamp + 1 : 0;
+  if (start_changestamp == 0 && !about_resource.get()) {
+    // Full update needs AboutResource. If this is a full update, we should just
+    // give up.
+    callback.Run(DRIVE_FILE_ERROR_FAILED);
+    return;
+  }
 
   // TODO(satorux): Use directory_fetch_info to start "fast-fetch" here.
-  LoadChangeListFromServer(start_changestamp,
-                           remote_changestamp,
+  LoadChangeListFromServer(about_resource.Pass(),
+                           start_changestamp,
                            callback);
 }
 
 void ChangeListLoader::LoadChangeListFromServer(
+    scoped_ptr<google_apis::AboutResource> about_resource,
     int64 start_changestamp,
-    int64 remote_changestamp,
     const FileOperationCallback& callback) {
   scoped_ptr<LoadFeedParams> load_params(new LoadFeedParams);
   load_params->start_changestamp = start_changestamp;
@@ -319,8 +323,8 @@ void ChangeListLoader::LoadChangeListFromServer(
       load_params.Pass(),
       base::Bind(&ChangeListLoader::UpdateMetadataFromFeedAfterLoadFromServer,
                  weak_ptr_factory_.GetWeakPtr(),
+                 base::Passed(&about_resource),
                  start_changestamp != 0,  // is_delta_feed
-                 remote_changestamp,
                  callback));
 }
 
@@ -471,8 +475,8 @@ void ChangeListLoader::SearchFromServer(
 }
 
 void ChangeListLoader::UpdateMetadataFromFeedAfterLoadFromServer(
+    scoped_ptr<google_apis::AboutResource> about_resource,
     bool is_delta_feed,
-    int64 feed_changestamp,
     const FileOperationCallback& callback,
     const ScopedVector<google_apis::ResourceList>& feed_list,
     DriveFileError error) {
@@ -485,9 +489,9 @@ void ChangeListLoader::UpdateMetadataFromFeedAfterLoadFromServer(
     return;
   }
 
-  UpdateFromFeed(feed_list,
+  UpdateFromFeed(about_resource.Pass(),
+                 feed_list,
                  is_delta_feed,
-                 feed_changestamp,
                  base::Bind(&ChangeListLoader::OnUpdateFromFeed,
                             weak_ptr_factory_.GetWeakPtr(),
                             callback));
@@ -733,9 +737,9 @@ void ChangeListLoader::SaveFileSystem() {
 }
 
 void ChangeListLoader::UpdateFromFeed(
+    scoped_ptr<google_apis::AboutResource> about_resource,
     const ScopedVector<google_apis::ResourceList>& feed_list,
     bool is_delta_feed,
-    int64 root_feed_changestamp,
     const base::Closure& update_finished_callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DCHECK(!update_finished_callback.is_null());
@@ -747,9 +751,9 @@ void ChangeListLoader::UpdateFromFeed(
   const bool should_notify_changed_directories = is_delta_feed;
 
   change_list_processor_->ApplyFeeds(
+      about_resource.Pass(),
       feed_list,
       is_delta_feed,
-      root_feed_changestamp,
       base::Bind(&ChangeListLoader::NotifyDirectoryChanged,
                  weak_ptr_factory_.GetWeakPtr(),
                  should_notify_changed_directories,