GitLab

Since OS X type sniffs to determine if a file is executable, we should
type sniff within a ZIP to identify DMGs with no file extension as
executable files.

Change-Id: I8e5e19205d46e60be8cccb3e259fcb705c1ca1f3
Bug: 866021
Reviewed-on: https://chromium-review.googlesource.com/1152183Reviewed-by: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Nathan Parker <nparker@chromium.org>
Commit-Queue: Daniel Rubery <drubery@chromium.org>
Cr-Commit-Position: refs/heads/master@{#590020}