[base] Use CheckedContiguousRange in Value

This change modifies the const overload of
base::Value::GetList() to return the newly introduced
base::CheckedContiguousRange() instead of base::span.

Furthermore this change updates callers to use this
new return value and performs some minor simplifications.

TBR=treib,stevenjb,blundell,benwells,noyau,agl

Bug: 990059
Change-Id: Iaf4577820fc579872d12d403cf8dd1aa9425b939
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1915759
Commit-Queue: Jan Wilken Dörrie <[email protected]>
Reviewed-by: Daniel Cheng <[email protected]>
Cr-Commit-Position: refs/heads/master@{#719972}
62 files changed