This patch fixes a `CHECK` for a range of a string when
`offset + length` overflows the `unsigned`.

(cherry picked from commit 59c286e8)

Bug: 355731798
Change-Id: If04222f10f2b73b6dcd6b412cf4d82fa5b71bbe2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5776342
Commit-Queue: Kent Tamura <tkent@chromium.org>
Auto-Submit: Koji Ishii <kojii@chromium.org>
Commit-Queue: Koji Ishii <kojii@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#1339526}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5804713


Reviewed-by: Koji Ishii <kojii@chromium.org>
Reviewed-by: Fahad Mansoor <fahadmansoor@google.com>
Auto-Submit: Roger Felipe Zanoni da Silva (xWF) <rzanoni@google.com>
Cr-Commit-Position: refs/branch-heads/6478@{#1958}
Cr-Branched-From: e6143acc-refs/heads/main@{#1300313}