Add bounds validation to AsyncPixelTransfersCompletedQuery::End

BUG=351852
R=jbauman@chromium.org, jorgelo@chromium.org

Review URL: https://codereview.chromium.org/198253002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256723 0039d316-1c4b-4281-b951-d872f2087c98
bool QueryManager::BeginQuery(Query* query) {
  DCHECK(query);
  if (!RemovePendingQuery(query)) {
    return false;
  }
  return query->Begin();
}

bool QueryManager::BeginQuery(Query* query) {
  DCHECK(query);
  if (!RemovePendingQuery(query)) {
    return false;
  }
  return query->Begin();
}
