Use a utility process for the Mojo v8 proxy resolver.

content/public/browser/utility_process_host.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_PUBLIC_BROWSER_UTILITY_PROCESS_HOST_H_
 #define CONTENT_PUBLIC_BROWSER_UTILITY_PROCESS_HOST_H_
 
 #include "base/environment.h"
 #include "base/process/launch.h"
 #include "base/threading/thread.h"
 #include "content/common/content_export.h"
 #include "ipc/ipc_sender.h"
 
 namespace base {
 class FilePath;
 class SequencedTaskRunner;
 }
 
 namespace content {
+class ServiceRegistry;
 class UtilityProcessHostClient;
 struct ChildProcessData;
 
 // This class acts as the browser-side host to a utility child process.  A
 // utility process is a short-lived process that is created to run a specific
 // task.  This class lives solely on the IO thread.
 // If you need a single method call in the process, use StartFooBar(p).
 // If you need multiple batches of work to be done in the process, use
 // StartBatchMode(), then multiple calls to StartFooBar(p), then finish with
 // EndBatchMode().
+// If you need to call Mojo services, use StartMojoMode() to start the child
+// process and GetServiceRegistry() to get the service registry to connect to
+// the child's Mojo services.
 //
 // Note: If your class keeps a ptr to an object of this type, grab a weak ptr to
 // avoid a use after free since this object is deleted synchronously but the
 // client notification is asynchronous.  See http://crbug.com/108871.
 class UtilityProcessHost : public IPC::Sender,
                            public base::SupportsWeakPtr<UtilityProcessHost> {
  public:
   // Used to create a utility process. |client| is optional. If supplied it will
   // be notified of incoming messages from the utility process.
   // |client_task_runner| is required if |client| is supplied and is the task
@@ skipping 25 matching lines @@
   // Make the process run elevated.
   virtual void ElevatePrivileges() = 0;
 #endif
 
   // Returns information about the utility child process.
   virtual const ChildProcessData& GetData() = 0;
 
 #if defined(OS_POSIX)
   virtual void SetEnv(const base::EnvironmentMap& env) = 0;
 #endif
+
+  // Starts the utility process in Mojo mode.
+  virtual bool StartMojoMode() = 0;
+
+  // Returns the ServiceRegistry for this process.

[Sam McNally, 2015/03/09 03:36:15]

Is this valid to call if the utility process wasn't started using
StartMojoMode()?

[Anand Mistry (off Chromium), 2015/03/10 07:24:24]

No. Added comment.

+  virtual ServiceRegistry* GetServiceRegistry() = 0;
 };
 
 };  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_UTILITY_PROCESS_HOST_H_