Enable GN check for webrtc/{p2p,system_wrappers}

Introduce new small header-only targets in system_wrappers:
:cpu_features_api
:field_trial_api
:metrics_api
to untangle and optimize dependencies but still satisfy GN check.

In webrtc/p2p, previously uncovered header "base/fakecandidatepair.h"
is added to :p2p_test_utils target.

Refactor system_wrappers so 'rtc_p2p' can depend on only
system_wrappers:field_trial_api instead of all of system_wrappers
(which led to a breakage in Chromium that called for the revert of
https://codereview.webrtc.org/2735583002).

BUG=webrtc:6828
NOTRY=True

Review-Url: https://codereview.webrtc.org/2739863002
Cr-Commit-Position: refs/heads/master@{#17812}
5 files changed
tree: 7a6d007ad10770d6927473494655433710edca25
  1. build_overrides/
  2. data/
  3. infra/
  4. resources/
  5. tools-webrtc/
  6. webrtc/
  7. .clang-format
  8. .git-blame-ignore-revs
  9. .gitignore
  10. .gn
  11. AUTHORS
  12. BUILD.gn
  13. check_root_dir.py
  14. cleanup_links.py
  15. codereview.settings
  16. DEPS
  17. LICENSE
  18. license_template.txt
  19. LICENSE_THIRD_PARTY
  20. OWNERS
  21. PATENTS
  22. PRESUBMIT.py
  23. pylintrc
  24. README.md
  25. WATCHLISTS
README.md

WebRTC is a free, open software project that provides browsers and mobile applications with Real-Time Communications (RTC) capabilities via simple APIs. The WebRTC components have been optimized to best serve this purpose.

Our mission: To enable rich, high-quality RTC applications to be developed for the browser, mobile platforms, and IoT devices, and allow them all to communicate via a common set of protocols.

The WebRTC initiative is a project supported by Google, Mozilla and Opera, amongst others.

Development

See http://www.webrtc.org/native-code/development for instructions on how to get started developing with the native code.

More info