Add PDF compositor service

content/public/browser/utility_process_host.h

Index: content/public/browser/utility_process_host.h
diff --git a/content/public/browser/utility_process_host.h b/content/public/browser/utility_process_host.h
index 5a404dbec1112aad88ed313fba155b8d18d75658..a35afd98ec363c4158385d0f64f1a19ffdfbc7e8 100644
--- a/content/public/browser/utility_process_host.h
+++ b/content/public/browser/utility_process_host.h
@@ -85,6 +85,9 @@ class UtilityProcessHost : public IPC::Sender {
   virtual void BindInterface(const std::string& interface_name,
                              mojo::ScopedMessagePipeHandle interface_pipe) = 0;
 
+  // Register mojo services that the utility process can use.

[Lei Zhang, 2017/05/04 02:13:13]

Mention this needs to run on the UI thread.

[Wei Li, 2017/05/04 18:18:28]

Done.

+  virtual void RegisterMojoServices() = 0;

[Lei Zhang, 2017/05/04 02:13:13]

It's weird to have this method as is:

1) The impl can be static.
2) The rest of the class runs on the IO thread. This is a bit of an odd ball as
a class method.

Can it leave elsewhere? Is it really tied to UtilityProcessHost?

[Wei Li, 2017/05/04 18:18:28]

As Ken said, once we can refactor those memory interfaces to some common
location, we can remove this. 

+
   // Set the name of the process to appear in the task manager.
   virtual void SetName(const base::string16& name) = 0;
 };