Code: void ChildThread::Shutdown() {
   file_system_dispatcher_.reset();
   quota_dispatcher_.reset();
 }

Vulnerability Type: DoS 
CWE ID: 
Summary: Use-after-free vulnerability in the ChildThread::Shutdown function in content/child/child_thread.cc in the filesystem API in Google Chrome before 35.0.1916.153 allows remote attackers to cause a denial of service or possibly have unspecified other impact via vectors related to a Blink shutdown.
Commit Message: [FileAPI] Clean up WebFileSystemImpl before Blink shutdown

WebFileSystemImpl should not outlive V8 instance, since it may have references to V8.
This CL ensures it deleted before Blink shutdown.

BUG=369525

Review URL: https://codereview.chromium.org/270633009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@269345 0039d316-1c4b-4281-b951-d872f2087c98