Revert "vm_tools: Remove GetDnsSettings dbus API from concierge"

This reverts commit 19b4c82f4f3c3792bcd69f313199cfc36fc350a3.

Reason for revert: This function is used by PluginVm
Please be careful before deleting functions.  The original commit
for this code does explain how it is used.
https://chromium.googlesource.com/chromiumos/platform2/+/42de9993dd102485ec307e96158491e8985cbf34

Original change's description:
> vm_tools: Remove GetDnsSettings dbus API from concierge
>
> This API appears to be unused, so delete it.
>
> BUG=none
> TEST=CQ
>
> Change-Id: I697aa2bceefb1cce44b6e0ab9cfc2434e1aa82a5
> Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform2/+/4190922
> Reviewed-by: Abhishek Bhardwaj <abhishekbh@chromium.org>
> Tested-by: Abhishek Bhardwaj <abhishekbh@chromium.org>
> Commit-Queue: Fergus Dall <sidereal@google.com>

Bug: b:243451864
Change-Id: I4cece6cf48a7b0916d48255d0dd322daae79af84
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform2/+/4235618
Commit-Queue: Joel Hockey <joelhockey@chromium.org>
Tested-by: Joel Hockey <joelhockey@chromium.org>
Auto-Submit: Joel Hockey <joelhockey@chromium.org>
Commit-Queue: Timothy Loh <timloh@chromium.org>
Reviewed-by: Fergus Dall <sidereal@google.com>
Reviewed-by: Timothy Loh <timloh@chromium.org>
NOKEYCHECK=True
GitOrigin-RevId: cc65166c5f0dd65e34f2c29a42bceaf21eb02920
2 files changed
tree: 97753a30a44d3586755098e9f71de2c54f8fc83d
  1. constants/
  2. dbus/
  3. mojo/
  4. src/
  5. switches/
  6. .gitignore
  7. BUILD.gn
  8. build.rs
  9. Cargo.toml
  10. DIR_METADATA
  11. LICENSE
  12. OWNERS
  13. README.md
  14. 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.