Revert of [Mojo Video Capture] Adapt video_capture service to refactored video capture stack (patchset #3 id:100001 of https://codereview.chromium.org/2818513003/ )

Reason for revert:
FakeVideoCaptureDeviceDescriptorTest.AccessIsRevokedOnSecondAccess test is flaky.
https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=service_unittests&tests=FakeVideoCaptureDeviceDescriptorTest.AccessIsRevokedOnSecondAccess

Original issue's description:
> [Mojo Video Capture] Adapt video_capture service to refactored video capture stack
>
> This CL is part of the Mojo Video Capture work. For the bigger picture,
> see [1] CL22b.
>
> Note: The video capture service implementation is currently in an incomplete and
> outdated state and its tests are disabled. With the refactoring of the legacy
> video capture stack now being complete, the next goal is to update the service
> implementation and fit it into the refactored stack.
>
> Changes in this CL:
> * Update Mojo interfaces to more closely resemble their native counterparts.
>   - video_capture.mojom.Device offers functionality similar to
>     VideoCaptureDeviceLauncher + LaunchedVideoCaptureDevice.
>   - video_capture.mojom.DeviceFactory offers functionality similar to
>     media::VideoCaptureProvider.
>   - video_capture.mojom.Receiver offers functionality similar to
>     media::VideoFrameReceiver.
> * In the service implementation, use a VideoCaptureSystem instead of a
>   VideoCaptureDeviceFactory directly.
> * Add new adapter classes for plumbing between Mojo service and its usage in
>   the native code.
> * Re-enable existing video_capture_unittests and add a few more.
>
> BUG=584797
> TEST=
>   service_unittests --gtest_filter="*Video*"
>   content_unittests --gtest_filter="*Video*"
>   content_browsertests --gtest_filter="VideoCaptureBrowserTest.*"
>
> [1] https://docs.google.com/a/chromium.org/document/d/1Qw7rw1AJy0QHXjha36jZNiEuxsxWslJ_X-zpOhijvI8/edit?usp=sharing
>
> Review-Url: https://codereview.chromium.org/2818513003
> Cr-Commit-Position: refs/heads/master@{#467398}
> Committed: https://chromium.googlesource.com/chromium/src/+/308b44e5bfb17c42ca3ea5b4fa5ed66c2698107b

TBR=mcasas@chromium.org,emircan@chromium.org,miu@chromium.org,ochang@chromium.org,chfremer@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=584797

Review-Url: https://codereview.chromium.org/2844813002
Cr-Commit-Position: refs/heads/master@{#467447}
30 files changed