Shut down proxy resolver utility processes when no longer needed.

net/proxy/in_process_mojo_proxy_resolver_factory.cc

Index: net/proxy/in_process_mojo_proxy_resolver_factory.cc
diff --git a/net/proxy/in_process_mojo_proxy_resolver_factory.cc b/net/proxy/in_process_mojo_proxy_resolver_factory.cc
index 47983c0169e93e7d415ef88cbb939c95c609399f..b38a09359bdce14aa1a7ec4dc3a13be4d873915f 100644
--- a/net/proxy/in_process_mojo_proxy_resolver_factory.cc
+++ b/net/proxy/in_process_mojo_proxy_resolver_factory.cc
@@ -25,13 +25,15 @@ InProcessMojoProxyResolverFactory::InProcessMojoProxyResolverFactory() {
 InProcessMojoProxyResolverFactory::~InProcessMojoProxyResolverFactory() =
     default;
 
-void InProcessMojoProxyResolverFactory::CreateResolver(
+scoped_ptr<base::ScopedClosureRunner>
+InProcessMojoProxyResolverFactory::CreateResolver(
     const mojo::String& pac_script,
     mojo::InterfaceRequest<interfaces::ProxyResolver> req,
     interfaces::HostResolverPtr host_resolver,
     interfaces::ProxyResolverFactoryRequestClientPtr client) {
   factory_->CreateResolver(pac_script, req.Pass(), host_resolver.Pass(),
                            client.Pass());
+  return nullptr;
 }
 
 }  // namespace net