Merge "Limit VCNs to one running at a given time" am: 9e6e3ce643 am: 4d16027790

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1767050

Change-Id: I89be4b61ec4e3a7ed24b817acf52a9c58fb5b4f2