[BackgroundSync] Move BackgroundSyncState from proto to mojo

[BackgroundSync] Move BackgroundSyncState from proto to mojo

There is a SyncState enum in background_sync.proto but we don't
actually need to store it to disk. So remove the protobuf enum to a
mojo definition (since we'll need it for mojo in registration.done).

BUG=502214
Committed: https://crrev.com/fffab7c9a274eaf70a12602c2dd3ba81caf318ed
Cr-Commit-Position: refs/heads/master@{#349653}

[jkarlin, 2015-09-17 00:52:32]

jkarlin@chromium.org changed reviewers:
+ mvanouwerkerk@chromium.org, tsepez@chromium.org

[jkarlin, 2015-09-17 00:52:33]

Michael: PTAL at everything
tsepez: PTAL at the mojo change

[Michael van Ouwerkerk, 2015-09-17 12:35:46]

lgtm

[Tom Sepez, 2015-09-17 18:14:27]

mojom lgtm

[jkarlin, 2015-09-17 18:19:59]

The CQ bit was checked by jkarlin@chromium.org

[commit-bot: I haz the power, 2015-09-17 18:20:28]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1348603003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1348603003/1

[commit-bot: I haz the power, 2015-09-17 18:36:36]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-09-17 18:36:37]

Try jobs failed on following builders:
  android_arm64_dbg_recipe on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/android_arm64_d...)
  android_chromium_gn_compile_dbg on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/android_chromiu...)
  android_compile_dbg on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/android_compile...)
  cast_shell_android on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/cast_shell_andr...)

[jkarlin, 2015-09-18 11:30:51]

The CQ bit was checked by jkarlin@chromium.org

[jkarlin, 2015-09-18 11:30:51]

The patchset sent to the CQ was uploaded after l-g-t-m from tsepez@chromium.org,
mvanouwerkerk@chromium.org
Link to the patchset: https://codereview.chromium.org/1348603003/#ps20001
(title: "Android fix")

[commit-bot: I haz the power, 2015-09-18 11:31:14]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1348603003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1348603003/20001

[commit-bot: I haz the power, 2015-09-18 12:11:48]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-09-18 12:12:21]

Patchset 2 (id:??) landed as
https://crrev.com/fffab7c9a274eaf70a12602c2dd3ba81caf318ed
Cr-Commit-Position: refs/heads/master@{#349653}