[Sync] Cleanup all tab sync enabling logic now that its on by default.

BUG=none
TEST=


Review URL: https://chromiumcodereview.appspot.com/10443046

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@139462 0039d316-1c4b-4281-b951-d872f2087c98
void ProfileSyncService::ClearServerData() {
  clear_server_data_state_ = CLEAR_CLEARING;
  clear_server_data_timer_.Start(FROM_HERE,
      base::TimeDelta::FromSeconds(kSyncClearDataTimeoutInSeconds), this,
      &ProfileSyncService::OnClearServerDataTimeout);
  backend_->RequestClearServerData();
}

void ProfileSyncService::ClearServerData() {
  clear_server_data_state_ = CLEAR_CLEARING;
  clear_server_data_timer_.Start(FROM_HERE,
      base::TimeDelta::FromSeconds(kSyncClearDataTimeoutInSeconds), this,
      &ProfileSyncService::OnClearServerDataTimeout);
  backend_->RequestClearServerData();
}
