Revert of Enable ChannelMojo on Linux (patchset #1 id:1 of https://codereview.chromium.org/684323002/)

Reason for revert:
Caused multiple layout test crashes on Linux

See http://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=css3%2Ffilters%2Feffect-reference-subregion-hidpi-hw.html%2Ccss3%2Ffilters%2Feffect-reference-subregion-hidpi.html%2Ccss3%2Fimages%2Fpixelated-hidpi.html%2Cfast%2Fhidpi%2Fimage-set-as-background.html%2Cfast%2Fhidpi%2Fimage-set-background-dynamic.html%2Cfast%2Fhidpi%2Fimage-set-background-repeat-without-size.html%2Cfast%2Fhidpi%2Fimage-set-background-repeat.html%2Cfast%2Fhidpi%2Fimage-set-border-image-comparison.html%2Cfast%2Fhidpi%2Fimage-set-border-image-dynamic.html%2Cfast%2Fhidpi%2Fimage-set-border-image-simple.html%2Cfast%2Fhidpi%2Fimage-set-in-content-dynamic.html%2Cfast%2Fhidpi%2Fimage-set-out-of-order.html%2Cfast%2Fhidpi%2Fimage-set-simple.html%2Cfast%2Fhidpi%2Fimage-set-without-specified-width.html%2Cfast%2Fhistory%2Freplacestate-nocrash.html%2Chttp%2Ftests%2Finspector%2Fnetwork%2Flong-script-content.html%2Chttp%2Ftests%2Fxmlhttprequest%2Fsimple-cross-origin-progress-events.html%2Csvg%2Fas-image%2Fsvg-as-image-canvas.html%2Csvg%2Fcss%2Fsvg-resource-fragment-identifier-img-src.html

Regressions: Unexpected crashes (19)
  css3/filters/effect-reference-subregion-hidpi-hw.html [ Crash ]
  css3/filters/effect-reference-subregion-hidpi.html [ Crash ]
  css3/images/pixelated-hidpi.html [ Crash ]
  fast/hidpi/image-set-as-background.html [ Crash ]
  fast/hidpi/image-set-background-dynamic.html [ Crash ]
  fast/hidpi/image-set-background-repeat-without-size.html [ Crash ]
  fast/hidpi/image-set-background-repeat.html [ Crash ]
  fast/hidpi/image-set-border-image-comparison.html [ Crash ]
  fast/hidpi/image-set-border-image-dynamic.html [ Crash ]
  fast/hidpi/image-set-border-image-simple.html [ Crash ]
  fast/hidpi/image-set-in-content-dynamic.html [ Crash ]
  fast/hidpi/image-set-out-of-order.html [ Crash ]
  fast/hidpi/image-set-simple.html [ Crash ]
  fast/hidpi/image-set-without-specified-width.html [ Crash ]
  fast/history/replacestate-nocrash.html [ Crash ]
  http/tests/inspector/network/long-script-content.html [ Crash ]
  http/tests/xmlhttprequest/simple-cross-origin-progress-events.html [ Crash ]
  svg/as-image/svg-as-image-canvas.html [ Crash ]
  svg/css/svg-resource-fragment-identifier-img-src.html [ Crash ]

Original issue's description:
> Enable ChannelMojo on Linux
>
> This change enables ChannelMojo on Linux.
> There could possibly be a perf slowdown, especially
> on latency metrics.
>
> If you're looking for the cause of some perf bot redness,
> probably this is that one. Please feel free to revert and
> let me know which benchmark was hit.
>
> BUG=664413003
> R=viettrungluu@chromium.org
>
> Committed: https://crrev.com/d4d85c640375ea7f9692e53860f4de058a7f0ea1
> Cr-Commit-Position: refs/heads/master@{#301992}

TBR=viettrungluu@chromium.org,morrita@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=664413003

Review URL: https://codereview.chromium.org/673903005

Cr-Commit-Position: refs/heads/master@{#302055}

1 files changed, 0 insertions, 4 deletions

diff --git a/ipc/mojo/ipc_channel_mojo.cc b/ipc/mojo/ipc_channel_mojo.cc
index e544340..4051bb5 100644
--- a/ipc/mojo/ipc_channel_mojo.cc
+++ b/ipc/mojo/ipc_channel_mojo.cc
@@ -176,11 +176,7 @@ void ChannelMojo::ChannelInfoDeleter::operator()(
 // static
 bool ChannelMojo::ShouldBeUsed() {
   // TODO(morrita): Turn this on for a set of platforms.
-#if defined(OS_LINUX)
-  return true;
-#else
   return false;
-#endif
 }
 
 // static