Add a bare-bones C++ style guide

BUG=none
NOTRY=true

Change-Id: I4488aff47db2b9220985156c5112db6d5a79a18e
Reviewed-on: https://chromium-review.googlesource.com/641872
Commit-Queue: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Niels Moller <nisse@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#19645}

OWNERS

@@ -12,3 +12,5 @@ per-file BUILD.gn=kjellander@webrtc.org
 per-file DEPS=*
 per-file pylintrc=kjellander@webrtc.org
 per-file WATCHLISTS=*
+per-file style-guide.md=danilchap@webrtc.org
+per-file style-guide.md=kwiberg@webrtc.org

README.md

@@ -21,3 +21,5 @@ started developing with the native code.
  * Samples and reference apps: https://github.com/webrtc
  * Mailing list: http://groups.google.com/group/discuss-webrtc
  * Continuous build: http://build.chromium.org/p/client.webrtc
+ * [Coding style guide](style-guide.md)
+ * [Code of conduct](CODE_OF_CONDUCT.md)

style-guide.md

@@ -0,0 +1,16 @@
+# WebRTC coding style guide
+
+## C++
+
+WebRTC follows the [Chromium][chr-style] and [Google][goog-style] C++
+style guides, unless an exception is listed below. In cases where they
+conflict, the Chromium style guide trumps the Google style guide, and
+the exceptions in this file trump them both.
+
+[chr-style]: https://chromium.googlesource.com/chromium/src/+/master/styleguide/c++/c++.md
+[goog-style]: https://google.github.io/styleguide/cppguide.html
+
+### Exceptions
+
+There are no exceptions yet. If and when exceptions are adopted,
+they'll be listed here.