Revert "Add SkSpan constructor that takes const Container&"

This reverts commit dead51f91b6b78c51d46d10867e539f63efed9b5.

Reason for revert: Breaking Chrome build.

Original change's description:
> Add SkSpan constructor that takes const Container&
>
> Change-Id: Iaa3b6183e8eb1cf17ec3a270dfbd384e7ad5d201
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/709200
> Reviewed-by: John Stiles <johnstiles@google.com>
> Commit-Queue: John Stiles <johnstiles@google.com>

Change-Id: Ib1e48367de5a503dd080bc82f19516c243537481
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/709898
Auto-Submit: Jim Van Verth <jvanverth@google.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
1 file changed