Revert of Prepare for injectable SW decoders (patchset #3 id:40001 of https://codereview.webrtc.org/3009973002/ )

Reason for revert:
Tentative revert since it seems to cause problems in Chrome, MAC.

https://build.chromium.org/p/chromium.webrtc.fyi/builders/Mac%20Tester/builds/42684

Original issue's description:
> Prepare for injectable SW decoders
>
> Pretty much mirrors the work done on the encoding side in CLs:
>
> "Clean up ownership of webrtc::VideoEncoder"
> https://codereview.webrtc.org/3007643002/
>
> "Let VideoEncoderSoftwareFallbackWrapper own the wrapped encoder"
> https://codereview.webrtc.org/3007683002/
>
> "WebRtcVideoEngine: Encapsulate logic for unifying internal and external video codecs"
> https://codereview.webrtc.org/3006713002/
>
> BUG=webrtc:7925
>
> Review-Url: https://codereview.webrtc.org/3009973002
> Cr-Commit-Position: refs/heads/master@{#19641}
> Committed: https://chromium.googlesource.com/external/webrtc/+/084c55a63a2d9bdc71579458406d44f8bab9f454

TBR=magjed@webrtc.org,andersc@webrtc.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=webrtc:7925

Review-Url: https://codereview.webrtc.org/3010953002
Cr-Commit-Position: refs/heads/master@{#19647}
8 files changed
tree: 279af95843c00dfbfb2001cb139ce1b612dab62d
  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