Only grant permissions to new extensions from sync if they have the expected version

TBRing a trivial change to theme_syncable_service.cc
[email protected]
BUG=529278

Review URL: https://codereview.chromium.org/1330163002

Cr-Commit-Position: refs/heads/master@{#348371}
9 files changed