The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/aac0c0f2f7a7b0a5de9424d77f0fe92cf739bb9b

commit aac0c0f2f7a7b0a5de9424d77f0fe92cf739bb9b
Author: Mohamed Amir Yosef <mamir@chromium.org>
Date: Fri Jul 06 15:04:18 2018

[Sync::USS] Switch GetLocalChangesCallback to be a OnceCallback

Currently ModelTypeProcessor::GetLocalChanges() is accepting
a repeating callback to be called when the local changes
are ready to be committed.

However, it should be a once callback.

Bug:  860675 
Change-Id: I4667c5cddc370b28b2091c207f1a97f75c501d05
Reviewed-on: https://chromium-review.googlesource.com/1127940
Reviewed-by: Mikel Astiz <mastiz@chromium.org>
Commit-Queue: Mohamed Amir Yosef <mamir@chromium.org>
Cr-Commit-Position: refs/heads/master@{#572973}
[modify] https://crrev.com/aac0c0f2f7a7b0a5de9424d77f0fe92cf739bb9b/components/sync/engine/fake_model_type_processor.cc
[modify] https://crrev.com/aac0c0f2f7a7b0a5de9424d77f0fe92cf739bb9b/components/sync/engine/fake_model_type_processor.h
[modify] https://crrev.com/aac0c0f2f7a7b0a5de9424d77f0fe92cf739bb9b/components/sync/engine/model_type_processor.h
[modify] https://crrev.com/aac0c0f2f7a7b0a5de9424d77f0fe92cf739bb9b/components/sync/engine/model_type_processor_proxy.cc
[modify] https://crrev.com/aac0c0f2f7a7b0a5de9424d77f0fe92cf739bb9b/components/sync/engine/model_type_processor_proxy.h
[modify] https://crrev.com/aac0c0f2f7a7b0a5de9424d77f0fe92cf739bb9b/components/sync/model_impl/client_tag_based_model_type_processor.cc
[modify] https://crrev.com/aac0c0f2f7a7b0a5de9424d77f0fe92cf739bb9b/components/sync/model_impl/client_tag_based_model_type_processor.h
[modify] https://crrev.com/aac0c0f2f7a7b0a5de9424d77f0fe92cf739bb9b/components/sync/test/engine/mock_model_type_processor.cc
[modify] https://crrev.com/aac0c0f2f7a7b0a5de9424d77f0fe92cf739bb9b/components/sync/test/engine/mock_model_type_processor.h
[modify] https://crrev.com/aac0c0f2f7a7b0a5de9424d77f0fe92cf739bb9b/components/sync_bookmarks/bookmark_model_type_processor.cc
[modify] https://crrev.com/aac0c0f2f7a7b0a5de9424d77f0fe92cf739bb9b/components/sync_bookmarks/bookmark_model_type_processor.h