Use ChannelMojo for the utility process.

content/public/common/child_process_host.h

Index: content/public/common/child_process_host.h
diff --git a/content/public/common/child_process_host.h b/content/public/common/child_process_host.h
index 9975faf762bf3077d1567f5b37c907f08e103866..7fbac4c8f6f9b259f7a14eb1043c4c0a1cb1e49d 100644
--- a/content/public/common/child_process_host.h
+++ b/content/public/common/child_process_host.h
@@ -81,6 +81,10 @@ class CONTENT_EXPORT ChildProcessHost : public IPC::Sender {
   // empty string otherwise
   virtual std::string CreateChannel() = 0;
 
+  // Creates the IPC channel on top of Mojo. Returns the Mojo channel token if
+  // succeeded, or an empty string on failure.
+  virtual std::string CreateChannelMojo(const std::string& child_token) = 0;
+
   // Returns true iff the IPC channel is currently being opened;
   virtual bool IsChannelOpening() = 0;