metrics: memd: Use system_api

Generate the metrics_event protobuf code in system_api instead of in
memd.

BUG=b:273672971
TEST=cargo test

Change-Id: I47decd289a8c8f358e1f0696dd104f483c2a6a58
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform2/+/5360436
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Vovo Yang <vovoy@chromium.org>
Tested-by: Vovo Yang <vovoy@chromium.org>
Reviewed-by: Miriam Zimmerman <mutexlox@chromium.org>
NOKEYCHECK=True
GitOrigin-RevId: edb3585caec84d750b7d5ed318f2a45563f31390
1 file changed
tree: 158e2382c8d8cb85786e3ab4fddf089432e71538
  1. constants/
  2. dbus/
  3. mojo/
  4. non_standard_ipc/
  5. proto/
  6. src/
  7. switches/
  8. .gitignore
  9. BUILD.gn
  10. build.rs
  11. Cargo.toml
  12. DIR_METADATA
  13. LICENSE
  14. OWNERS
  15. README.md
  16. system_api.pc
README.md

This directory (platform2/system_api) contains constants and definitions like D-Bus service names that are shared between Chromium and Chromium OS.

This directory is only for things like headers and .proto files. No implementation should be added.

When writting a .proto file make sure to use:

option optimize_for = LITE_RUNTIME;

This will force usage of a lite protobuf instead of a full/heavy weight protobuf. The browser only links against the light version, so you will get cryptic link errors about missing parts of Message if you define a protobuf here and then try to use it in Chrome. Currently CrOS links against the full protobuffer library, but that might change in the future.

When declaring a protobuf, avoid use of required unless it is exactly what you mean. “Required is Forever” and very rarely should actually be used. Consult Protocol Buffer Basics: C++ for a detailed of this issue.