[SyncFS] Unconditionally demote remote file trackers on remote-to-local sync

chrome/browser/sync_file_system/drive_backend/conflict_resolver_unittest.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/sync_file_system/drive_backend/conflict_resolver.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/file_util.h"
 #include "base/files/scoped_temp_dir.h"
@@ skipping 191 matching lines @@
         file_change, local_path, url));
     syncer->RunPreflight(SyncTaskToken::CreateForTesting(
         CreateResultReceiver(&status)));
     base::RunLoop().RunUntilIdle();
     if (status == SYNC_STATUS_OK)
       remote_change_processor_->ClearLocalChanges(url);
     return status;
   }
 
   void RunRemoteToLocalSyncerUntilIdle() {
-    SyncStatusCode status = SYNC_STATUS_UNKNOWN;
-    while (status != SYNC_STATUS_NO_CHANGE_TO_SYNC)
+    const int kRetryLimit = 100;
+    SyncStatusCode status;
+    int retry_count = 0;
+    MetadataDatabase* metadata_database = context_->GetMetadataDatabase();
+    do {
+      if (retry_count++ > kRetryLimit)
+        break;
       status = RunRemoteToLocalSyncer();
+    } while (status == SYNC_STATUS_OK ||
+             status == SYNC_STATUS_RETRY ||
+             metadata_database->PromoteLowerPriorityTrackersToNormal());
+    EXPECT_EQ(SYNC_STATUS_NO_CHANGE_TO_SYNC, status);
   }
 
   SyncStatusCode RunConflictResolver() {
     SyncStatusCode status = SYNC_STATUS_UNKNOWN;
     ConflictResolver resolver(context_.get());
     resolver.RunPreflight(SyncTaskToken::CreateForTesting(
         CreateResultReceiver(&status)));
     base::RunLoop().RunUntilIdle();
     return status;
   }
@@ skipping 288 matching lines @@
 
   EXPECT_EQ(4, CountParents(file));
 
   EXPECT_EQ(SYNC_STATUS_OK, RunConflictResolver());
 
   EXPECT_EQ(1, CountParents(file));
 }
 
 }  // namespace drive_backend
 }  // namespace sync_file_system