Implement SyncEngine::DidProcessRemoteChange

TEST=None
BUG=240165

Review URL: https://codereview.chromium.org/77663003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236755 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 236755