Shut down proxy resolver utility processes when no longer needed.

chrome/browser/net/utility_process_mojo_proxy_resolver_factory.h

 // Copyright 2015 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 CHROME_BROWSER_NET_UTILITY_PROCESS_MOJO_PROXY_RESOLVER_FACTORY_H_
 #define CHROME_BROWSER_NET_UTILITY_PROCESS_MOJO_PROXY_RESOLVER_FACTORY_H_
 
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "base/timer/timer.h"
 #include "net/proxy/mojo_proxy_resolver_factory.h"
 
+namespace content {
+class UtilityProcessHost;
+}
+
 template <typename Type>
 struct DefaultSingletonTraits;
 
 // A factory used to create connections to Mojo proxy resolver services run in a
 // utility process. All Mojo proxy resolver services will be run in the same
 // utility process. Utility process crashes are detected and the utility
 // process is automatically restarted.
 class UtilityProcessMojoProxyResolverFactory
     : public net::MojoProxyResolverFactory,
       public mojo::ErrorHandler {
  public:
   static UtilityProcessMojoProxyResolverFactory* GetInstance();
 
   // Overridden from net::MojoProxyResolverFactory:
-  void Create(mojo::InterfaceRequest<net::interfaces::ProxyResolver> req,
-              net::interfaces::HostResolverPtr host_resolver) override;
+  scoped_ptr<base::ScopedClosureRunner> Create(
+      mojo::InterfaceRequest<net::interfaces::ProxyResolver> req,
+      net::interfaces::HostResolverPtr host_resolver) override;
 
  private:
   friend struct DefaultSingletonTraits<UtilityProcessMojoProxyResolverFactory>;
   UtilityProcessMojoProxyResolverFactory();
   ~UtilityProcessMojoProxyResolverFactory() override;
 
   // Overridden from mojo::ErrorHandler:
   void OnConnectionError() override;
 
+  // Invoked each time a proxy resolver is destroyed.
+  void OnResolverDestroyed();
+
+  // Invoked once an idle timeout has elapsed after all proxy resolvers are
+  // destroyed.
+  void OnIdleTimeout();
+
   // Creates a new utility process and connects to its Mojo proxy resolver
   // factory.
   void CreateProcessAndConnect();
 
   net::interfaces::ProxyResolverFactoryPtr resolver_factory_;
 
+  base::WeakPtr<content::UtilityProcessHost> utility_process_host_;
+  size_t num_proxy_resolvers_ = 0;
+
+  base::OneShotTimer<UtilityProcessMojoProxyResolverFactory> idle_timer_;
+
   DISALLOW_COPY_AND_ASSIGN(UtilityProcessMojoProxyResolverFactory);
 };
 
 #endif  // CHROME_BROWSER_NET_UTILITY_PROCESS_MOJO_PROXY_RESOLVER_FACTORY_H_