Revert "Revert "Make shell child processes slaves.""

shell/child_process_host.h

Index: shell/child_process_host.h
diff --git a/shell/child_process_host.h b/shell/child_process_host.h
index c0cef795f8986f13a3ea3e0937e0a3e3d2863aa9..d5e45624e2f9721858e511b2913c9058ab843b54 100644
--- a/shell/child_process_host.h
+++ b/shell/child_process_host.h
@@ -7,6 +7,8 @@
 
 #include <stdint.h>
 
+#include <string>
+
 #include "base/macros.h"
 #include "base/process/process.h"
 #include "mojo/edk/embedder/channel_info_forward.h"
@@ -64,7 +66,7 @@ class ChildProcessHost : public mojo::ErrorHandler {
   // Callback for |mojo::embedder::CreateChannel()|.
   void DidCreateChannel(mojo::embedder::ChannelInfo* channel_info);
 
-  bool DoLaunch();
+  bool DoLaunch(const std::string& child_connection_id);
 
   void AppCompleted(int32_t result);