Enable ChannelMojo

As we addressed certain amount of the performance problem,
it's time to give it another try.

R=viettrungluu@chromium.org
BUG=377980

Review URL: https://codereview.chromium.org/857483004

Cr-Commit-Position: refs/heads/master@{#313184}

ipc/mojo/ipc_channel_mojo.cc

@@ -173,8 +173,8 @@ void ChannelMojo::ChannelInfoDeleter::operator()(
 
 // static
 bool ChannelMojo::ShouldBeUsed() {
-  // TODO(morrita): Turn this on for a set of platforms.
-  return false;
+  // TODO(morrita): Remove this if it sticks.
+  return true;
 }
 
 // static