[media] Convert std::unique_ptr<T[]> to HeapArray<T> in media/base/...

See
https://docs.google.com/document/d/1YsPR8GoN8VTP1ABKCISaQkuBif1Cn80cTxTjsM8QT4s
for an explanation on why this is favorable.

Bug: b/326459492, b/326459327, b/326459127, b/326459386, b/326459268
Change-Id: I88db2042b67ff3706c5ee2c122c18dcd80682cd9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5450966


Commit-Queue: Feras Aldahlawi <feras@chromium.org>
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Reviewed-by: John Rummell <jrummell@chromium.org>
Reviewed-by: Mark Foltz <mfoltz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1289603}