The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4feacb1e9db9b1ecc40ce0531fa2e04e4ee8ee0e

commit 4feacb1e9db9b1ecc40ce0531fa2e04e4ee8ee0e
Author: pnoland <pnoland@chromium.org>
Date: Fri Oct 21 21:50:03 2016

[sync] Add store version to model type store backend

Add the ModelTypeStoreSchemaDescriptor protobuf, and add a basic
framework for performing migration. Add a Paranoid PRESUBMIT test to
make sure the record identifier for the db version won't be reused.

R=pavely@chromium.org

BUG= 656737 

Review-Url: https://chromiumcodereview.appspot.com/2426613003
Cr-Commit-Position: refs/heads/master@{#426900}

[modify] https://crrev.com/4feacb1e9db9b1ecc40ce0531fa2e04e4ee8ee0e/components/sync/PRESUBMIT.py
[modify] https://crrev.com/4feacb1e9db9b1ecc40ce0531fa2e04e4ee8ee0e/components/sync/PRESUBMIT_test.py
[modify] https://crrev.com/4feacb1e9db9b1ecc40ce0531fa2e04e4ee8ee0e/components/sync/model/model_type_store.h
[modify] https://crrev.com/4feacb1e9db9b1ecc40ce0531fa2e04e4ee8ee0e/components/sync/model_impl/model_type_store_backend.cc
[modify] https://crrev.com/4feacb1e9db9b1ecc40ce0531fa2e04e4ee8ee0e/components/sync/model_impl/model_type_store_backend.h
[modify] https://crrev.com/4feacb1e9db9b1ecc40ce0531fa2e04e4ee8ee0e/components/sync/model_impl/model_type_store_backend_unittest.cc
[add] https://crrev.com/4feacb1e9db9b1ecc40ce0531fa2e04e4ee8ee0e/components/sync/protocol/model_type_store_schema_descriptor.proto
[modify] https://crrev.com/4feacb1e9db9b1ecc40ce0531fa2e04e4ee8ee0e/components/sync/protocol/protocol_sources.gni