Revert of Re-enable ChannelMojo (patchset #1 id:1 of https://codereview.chromium.org/1021393002/)

Reason for revert:
speculative revert for "Too many open files" on various Mac bots.
e.g. http://build.chromium.org/p/chromium.webkit/builders/WebKit%20Mac10.9/builds/17511/steps/webkit_tests/logs/stdio

Original issue's description:
> Re-enable ChannelMojo
>
> It was disabled due to crbug.com/466814 that is now fixed.
> It's time to turn it on again.
>
> R=viettrungluu@chromium.org
> BUG=466814,377980
>
> Committed: https://crrev.com/c99c93842fa50f85888d069f0be962462f92a643
> Cr-Commit-Position: refs/heads/master@{#322092}

TBR=viettrungluu@chromium.org,morrita@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=466814,377980

Review URL: https://codereview.chromium.org/1029263008

Cr-Commit-Position: refs/heads/master@{#322113}

ipc/mojo/ipc_channel_mojo.cc

@@ -192,7 +192,8 @@ void ChannelMojo::ChannelInfoDeleter::operator()(
 // static
 bool ChannelMojo::ShouldBeUsed() {
   // TODO(morrita): Remove this if it sticks.
-  return true;
+  // ChannelMojo is currently disabled due to http://crbug.com/466814.
+  return false;
 }
 
 // static