Removing the unused media::ColorSpace mojom type.

This is a cherrypick/split from
https://chromium-review.googlesource.com/c/chromium/src/+/2108507

Change-Id: Ib7cc2e5dc93f507726cb417446cb1ad6e1ba6a74
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2109696Reviewed-by: Oliver Chang <ochang@chromium.org>
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Commit-Queue: Mark Brand <markbrand@google.com>
Cr-Commit-Position: refs/heads/master@{#751956}

media/mojo/mojom/media_types.mojom

@@ -28,10 +28,6 @@ enum BufferingStateChangeReason;
 [Native]
 enum ChannelLayout;
 
-// See media/base/video_types.h for descriptions.
-[Native]
-enum ColorSpace;
-
 // See media/base/decode_status.h for descriptions.
 [Native]
 enum DecodeStatus;

media/mojo/mojom/media_types.typemap

@@ -50,7 +50,6 @@ type_mappings = [
   "media.mojom.BufferingState=::media::BufferingState",
   "media.mojom.BufferingStateChangeReason=::media::BufferingStateChangeReason",
   "media.mojom.ChannelLayout=::media::ChannelLayout",
-  "media.mojom.ColorSpace=::media::ColorSpace",
   "media.mojom.DecodeStatus=::media::DecodeStatus",
   "media.mojom.EncryptionScheme=::media::EncryptionScheme",
   "media.mojom.MediaContainerName=::media::container_names::MediaContainerName",