Remove unnecessary use of unique ptr with base::Value::Dict

As well as some unnecessary string allocations.

Bug: 40258809
Change-Id: I91c966c236b85cfc0a94ef3ab73a97801c828b1d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6403273
Reviewed-by: Takashi Toyoshima <toyoshim@chromium.org>
Commit-Queue: Andrew Paseltiner <apaseltiner@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1439325}
NOKEYCHECK=True
GitOrigin-RevId: 20fa870c10d83965c221575d7080bacb03fa7101
2 files changed