drive: Trigger "fast fetch" if remote update came during full loading.

chrome/browser/chromeos/drive/directory_loader.cc

Index: chrome/browser/chromeos/drive/directory_loader.cc
diff --git a/chrome/browser/chromeos/drive/directory_loader.cc b/chrome/browser/chromeos/drive/directory_loader.cc
index d67d359cf6fd02b5c89975821ef79ab7c522dcdb..6844368e7da3eb08ded96171797e7be72a9234d0 100644
--- a/chrome/browser/chromeos/drive/directory_loader.cc
+++ b/chrome/browser/chromeos/drive/directory_loader.cc
@@ -396,9 +396,12 @@ void DirectoryLoader::ReadDirectoryAfterCheckLocalState(
   DirectoryFetchInfo directory_fetch_info(
       local_id, entry->resource_id(), remote_changestamp);
 
-  // If the directory's changestamp is new enough, just schedule to run the
-  // callback, as there is no need to fetch the directory.
-  if (directory_changestamp + kMinimumChangestampGap > remote_changestamp) {
+  // If the directory's changestamp is up-to-date or the global changestamp of
+  // the metadata DB is new enough (which means the normal changelist loading
+  // should finish very soon), just schedule to run the callback, as there is no
+  // need to fetch the directory.
+  if (directory_changestamp >= remote_changestamp ||
+      *local_changestamp + kMinimumChangestampGap > remote_changestamp) {
     OnDirectoryLoadComplete(local_id, FILE_ERROR_OK);
   } else {
     // Start fetching the directory content, and mark it with the changestamp