RELAND: media: rename VP9 s/IsFrameContextRequired/NeedsCompressedHeaderParsed/

This CL relands the original CL verbatim, since the culprit was
its parent.

Original CL description ------------------------------------------------

This CL renames VP9Decoder::VP9Accelerator::IsFrameContextRequired()
to better reflect what it does in the code, i.e. VP9Decoder uses it to
instruct its VP9Parser whether to parse or not VP9s compressed header.
All implementors return false except V4L2 legacy backends, which are
also name-updates to better reflect the semantics.

No new functionality intended, only cosmetic changes.

Bug: b:214332361
Change-Id: I0fb500bd52b138a8f73fa17907a05b9ba815e8c0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3499056
Reviewed-by: Steve Cho <stevecho@chromium.org>
Commit-Queue: Miguel Casas-Sanchez <mcasas@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#978502}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3511049
Cr-Commit-Position: refs/heads/main@{#980369}