[Fuchsia] Create //third_party/fuchsia-gn-sdk directory

Copy Fuchsia GN SDK files for generating GN targets for .fidl files
from fuchsia.git. These files will be removed from Fuchsia and be
maintained in Chromium.

The contents of
https://fuchsia.googlesource.com/fuchsia/+/a1d52817323cccc0a393b232363e0f2278dec14c/scripts/sdk/gn/base/build/
are copied unmodified to `src/`, with an exception of
`enable_coverage_data.cml` since it is being actively deprecated.
Modifications to work in Chromium will be made in a follow-up change.

Bug: 1432399
Change-Id: I51258f75668d1b20f90b0201a736e04aaec2e5b5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4492524
Commit-Queue: Chong Gu <chonggu@google.com>
Reviewed-by: Nico Weber <thakis@chromium.org>
Reviewed-by: David Dorwin <ddorwin@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1145325}
NOKEYCHECK=True
GitOrigin-RevId: c12e1f25432f0c108ac0b0ca25a8b4196bebf39f
24 files changed
tree: 31cf6ffd408c4c88b187494a84b0e4897bf8da0c
  1. src/
  2. DIR_METADATA
  3. LICENSE
  4. OWNERS
  5. README.chromium