Code: void AppCacheHost::SelectCacheForWorker(int parent_process_id,
                                         int parent_host_id) {
   DCHECK(pending_start_update_callback_.is_null() &&
          pending_swap_cache_callback_.is_null() &&
          pending_get_status_callback_.is_null() &&
         !is_selection_pending() && !was_select_cache_called_);
 
   was_select_cache_called_ = true;
   parent_process_id_ = parent_process_id;
   parent_host_id_ = parent_host_id;
   FinishCacheSelection(NULL, NULL);
 }

Vulnerability Type: DoS 
CWE ID: 
Summary: Use-after-free vulnerability in the AppCache implementation in Google Chrome before 47.0.2526.73 allows remote attackers with renderer access to cause a denial of service or possibly have unspecified other impact by leveraging incorrect AppCacheUpdateJob behavior associated with duplicate cache selection.
Commit Message: Fix possible map::end() dereference in AppCacheUpdateJob triggered by a compromised renderer.

BUG=551044

Review URL: https://codereview.chromium.org/1418783005

Cr-Commit-Position: refs/heads/master@{#358815}