Gracefully deal with clearing content settings for unregistered extensions.


BUG=128652


Review URL: https://chromiumcodereview.appspot.com/10907093

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@155341 0039d316-1c4b-4281-b951-d872f2087c98
void ContentSettingsStore::RemoveObserver(Observer* observer) {
  DCHECK(OnCorrectThread());
  observers_.RemoveObserver(observer);
}

void ContentSettingsStore::RemoveObserver(Observer* observer) {
  DCHECK(OnCorrectThread());
  observers_.RemoveObserver(observer);
}
