SyncFS: Drop a remote delete change when it has unknown resource ID.

This is prerequisite patch for https://codereview.chromium.org/13986011/


BUG=none
TEST=unit_tests --gtest_filter=\*DriveFileSyncService\*

Review URL: https://chromiumcodereview.appspot.com/14334007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@196723 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 12 insertions, 3 deletions

diff --git a/chrome/browser/sync_file_system/drive_file_sync_service.cc b/chrome/browser/sync_file_system/drive_file_sync_service.cc
index 750ad5b..6a68d87 100644
--- a/chrome/browser/sync_file_system/drive_file_sync_service.cc
+++ b/chrome/browser/sync_file_system/drive_file_sync_service.cc
@@ -1889,6 +1889,11 @@ bool DriveFileSyncService::AppendRemoteChangeInternal(
       remote_resource_id != local_resource_id)
     return false;
 
+  // Drop any change if the change is for deletion and local resource id is
+  // empty.
+  if (is_deleted && local_resource_id.empty())
+    return false;
+
   FileChange file_change(CreateFileChange(is_deleted));
 
   if (is_deleted) {
diff --git a/chrome/browser/sync_file_system/drive_file_sync_service_mock_unittest.cc b/chrome/browser/sync_file_system/drive_file_sync_service_mock_unittest.cc
index 55fe287..c3bcd28 100644
--- a/chrome/browser/sync_file_system/drive_file_sync_service_mock_unittest.cc
+++ b/chrome/browser/sync_file_system/drive_file_sync_service_mock_unittest.cc
@@ -1263,13 +1263,17 @@ TEST_F(DriveFileSyncServiceMockTest, RemoteChange_Override) {
       kOrigin, kFilePath, true /* is_deleted */,
       kFileResourceId, 6, "deleted_file_md5"));
 
-  // Expect not to drop these changes even if they have different resource IDs.
-  EXPECT_TRUE(AppendIncrementalRemoteChange(
+  // Expect to drop this delete change since it has a different resource ID with
+  // the previous one.
+  EXPECT_FALSE(AppendIncrementalRemoteChange(
       kOrigin, kFilePath, true /* is_deleted */,
       kFileResourceId2, 7, "deleted_file_md5"));
+
+  // Expect not to drop this change even if it has a different resource ID with
+  // the previous one.
   EXPECT_TRUE(AppendIncrementalRemoteChange(
       kOrigin, kFilePath, false /* is_deleted */,
-      kFileResourceId, 8, "updated_file_md5"));
+      kFileResourceId2, 8, "updated_file_md5"));
 }
 
 TEST_F(DriveFileSyncServiceMockTest, RemoteChange_Folder) {