Reland "Remove redundant enum defined in both mojom and .h: MediaStreamRequestResult"

This CL removes the redundant enum MediaStreamRequestResult, defined in [1],
in favor of the mojom existing variant in [2].

[1] third_party/blink/public/common/mediastream/media_stream_request.h
[2] third_party/blink/public/mojom/mediastream/media_stream.mojom

The associated typemap [3] and traits declarations [4][5] are also removed.

[3] third_party/blink/public/common/mediastream/media_stream.typemap
[4] third_party/blink/common/mediastream/media_stream_mojom_traits.cc
[5] hird_party/blink/public/common/mediastream/media_stream_mojom_traits.h

[email protected]

BUG=923394,919392

This is a reland of https://crrev.com/c/1639237.

Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1639237
Commit-Queue: Antonio Gomes <[email protected]>
Reviewed-by: Kentaro Hara <[email protected]>
Reviewed-by: Guido Urdaneta <[email protected]>
Cr-Original-Commit-Position: refs/heads/master@{#665431}
Change-Id: I7af5c650648c53f1ef9763fb5a12b32fa0c0544c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1642734
Cr-Commit-Position: refs/heads/master@{#666253}
65 files changed