base: remove NaCl from BUILD.gn, as well as NaCl-only source files

GN cleanups are deferred to a followup CL to make this CL easier to
diff.

Bug: 40511454
Change-Id: I6b6774a622920b149f5c9650a449bb8e41496fad
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6658300
Reviewed-by: Kyle Charbonneau <[email protected]>
Commit-Queue: Daniel Cheng <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1476675}
NOKEYCHECK=True
GitOrigin-RevId: 9486028f224197e09f7a7f79fb60310a7988dc15
2 files changed