Revert of Remove typedefs.h from webrtc/ root (part 1) (patchset #3 id:40001 of https://codereview.webrtc.org/3007253002/ )

Reason for revert:
Breaks the Chromium WebRTC FYI bots:
https://build.chromium.org/p/chromium.webrtc.fyi/builders/ios-simulator/builds/2834
https://build.chromium.org/p/chromium.webrtc.fyi/builders/Win%20Builder/builds/11775

Example:
FAILED: obj/third_party/libjingle_xmpp/libjingle_xmpp_unittests/xmpplogintask_unittest.obj
ninja -t msvc -e environment.x86 -- E:\b\c\goma_client/gomacc.exe "e:\b\c\win_toolchain\vs_files\f53e4598951162bad6330f7a167486c7ae5db1e5\vc\bin\amd64_x86/cl.exe" /nologo /showIncludes  @obj/third_party/libjingle_xmpp/libjingle_xmpp_unittests/xmpplogintask_unittest.obj.rsp /c ../../third_party/libjingle_xmpp/xmpp/xmpplogintask_unittest.cc /Foobj/third_party/libjingle_xmpp/libjingle_xmpp_unittests/xmpplogintask_unittest.obj /Fd"obj/third_party/libjingle_xmpp/libjingle_xmpp_unittests_cc.pdb"
../../third_party/libjingle_xmpp/xmpp/xmpplogintask_unittest.cc(95): error C3861: 'FALLTHROUGH': identifier not found

Original issue's description:
> Remove typedefs.h from webrtc/ root (part 1)
>
> Split out webrtc-specific #defines from typedefs.h, into rtc_base/annotations.h and rtc_base/arch.h.
> Also removes the curiously named WEBRTC_CPU_DETECTION #define.
>
> BUG=webrtc:6854
>
> Review-Url: https://codereview.webrtc.org/3007253002
> Cr-Commit-Position: refs/heads/master@{#19752}
> Committed: https://chromium.googlesource.com/external/webrtc/+/a895836321e68b67ca2081c3bdbf6c08d8ee4b57

TBR=kwiberg@webrtc.org,solenberg@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:6854

Review-Url: https://codereview.webrtc.org/3013543002
Cr-Commit-Position: refs/heads/master@{#19754}
17 files changed
tree: f602ff0c12c50659494eab6e94b244c0c8e0139d
  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. .vpython
  12. AUTHORS
  13. BUILD.gn
  14. CODE_OF_CONDUCT.md
  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. style-guide.md
  26. 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