Add mode handler for removal of uploaded file if user clicks 'Cancel'. bugid:80850
Handler code to delete uploaded file if user clicks 'Cancel'. bugid:80850
Modify 'Cancel' button handling on asset options page to remove new uploaded file if user clicks 'Cancel'.
Revert "Modify 'Cancel' button handling on asset options page to remove new uploaded file if user clicks 'Cancel'."

This reverts commit 8bfa2b4c688708ec04031cd680802489d28a38fe.
Modify 'Cancel' button handling on asset options page to remove new uploaded file if user clicks 'Cancel'. bugid:80850
Add security checks and add code comments.
Revert "Add security checks and add code comments."

This reverts commit 6162c5e335ff5d1ae55ab0dd9bd9ce20806fce53.
Add security checks and add code comments. bugid:80850
Merge branch 'cancel_upload' into develop