Re-enable ChannelMojo between Service process <-> service utility process.

ChannelMojo between Service process <-> service utility process is
currently disabled because:
  -- Service process starts service utility process with a command line
     containing kMojoChannelToken switch but no kMojoApplicationChannelToken,
     because they are not in ServiceManager world now.
  -- But, service utility process(ChildThreadImpl) will disable ChannelMojo
     because of lack of kMojoApplicationChannelToken switch.

This CL lets ChildThreadImpl enable ChannelMojo also for a kMojoChannelToken
switch.

BUG=646833
TBR=ben@chromium.org

Review-Url: https://codereview.chromium.org/2366443004
Cr-Commit-Position: refs/heads/master@{#420566}

content/child/child_thread_impl.cc

@@ -296,10 +296,11 @@ ChildThreadImpl::Options::Options()
     : channel_name(base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
           switches::kProcessChannelID)),
       use_mojo_channel(base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kMojoApplicationChannelToken)),
+                           switches::kMojoApplicationChannelToken) ||
+                       base::CommandLine::ForCurrentProcess()->HasSwitch(
+                           switches::kMojoChannelToken)),
       auto_start_mojo_shell_connection(true),
-      connect_to_browser(false) {
-}
+      connect_to_browser(false) {}
 
 ChildThreadImpl::Options::Options(const Options& other) = default;