Add VideoProcessorIntegrationTest for MediaCodec implementations.

* Add VideoProcessorIntegrationTestMediaCodec tests, including
  a standard foreman test and a forced SW fallback test.
* Morph PlotVideoProcessorIntegrationTest into
  VideoProcessorIntegrationTestParameterized. This test is intended
  to be patched locally, depending on what metric is of interest.
  It is run on the bots to ensure that it doesn't break.
* Remove the plot_videoprocessor_integrationtest binary. The test
  above is instead moved to the modules_tests binary.

BUG=webrtc:6634

Review-Url: https://codereview.webrtc.org/3011043002
Cr-Original-Commit-Position: refs/heads/master@{#19727}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: df232992597bd2865fdbede3e9d7e45445e4f122
7 files changed