Revert of Implement IPC::ParamTraits<mojo::MessagePipeHandle> (patchset #4 id:60001 of https://codereview.chromium.org/1051443003/)

Reason for revert:
This broke the tests again, looks like ParamTraitInvalidMesssagePipe was fixed, but ParamTraitValidMessagePipe wasn't.

https://build.chromium.org/p/chromium.win/builders/XP%20Tests%20%281%29/builds/36687/steps/ipc_mojo_unittests/logs/IPCChannelMojoTest.ParamTraitValidMessagePipe

https://build.chromium.org/p/chromium.win/builders/XP%20Tests%20%281%29/builds/36687

Original issue's description:
> Implement IPC::ParamTraits<mojo::MessagePipeHandle>
>
> This allows MessagePipeHandle to be an IPC message member.
> Note that this assumes underlying channel being a ChannelMojo
> and can be used in content/  only after ChannelMojo settles.
>
> BUG=448190
> TEST=IPCChannelMojoTest.ParamTrait*
> R=viettrungluu@chromium.org
>
> Committed: https://crrev.com/5656ae68841a3e3ddaac75cf2983d9052d71d0d5
> Cr-Commit-Position: refs/heads/master@{#323265}
>
> Committed: https://crrev.com/2b85d21119ce534940ccd2ff57727cd4b428081c
> Cr-Commit-Position: refs/heads/master@{#323370}

TBR=viettrungluu@chromium.org,morrita@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=448190

Review URL: https://codereview.chromium.org/1054983003

Cr-Commit-Position: refs/heads/master@{#323484}


CrOS-Libchrome-Original-Commit: ef026b654f3e8e0d6f83114bf0f148b26a5cc1be
3 files changed
tree: feb27c4aae4b1066be513284364418c118f7e464
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/