Attempting to re-land a small portion of this change... Simply add links from

net/http/http_proxy_client_socket_pool.h

Index: net/http/http_proxy_client_socket_pool.h
diff --git a/net/http/http_proxy_client_socket_pool.h b/net/http/http_proxy_client_socket_pool.h
index 1b0afb43735165a455cbdcd92acc9d36d79a9b43..48a4b274afaaf952bcaf09245e811bee3eb9fb0e 100644
--- a/net/http/http_proxy_client_socket_pool.h
+++ b/net/http/http_proxy_client_socket_pool.h
@@ -170,7 +170,9 @@ class HttpProxyConnectJob : public ConnectJob {
   DISALLOW_COPY_AND_ASSIGN(HttpProxyConnectJob);
 };
 
-class NET_EXPORT_PRIVATE HttpProxyClientSocketPool : public ClientSocketPool {
+class NET_EXPORT_PRIVATE HttpProxyClientSocketPool
+    : public ClientSocketPool,
+      public LayeredPool {
  public:
   HttpProxyClientSocketPool(
       int max_sockets,
@@ -205,6 +207,8 @@ class NET_EXPORT_PRIVATE HttpProxyClientSocketPool : public ClientSocketPool {
 
   virtual void Flush() OVERRIDE;
 
+  virtual bool IsStalled() const OVERRIDE;
+
   virtual void CloseIdleSockets() OVERRIDE;
 
   virtual int IdleSocketCount() const OVERRIDE;
@@ -216,6 +220,10 @@ class NET_EXPORT_PRIVATE HttpProxyClientSocketPool : public ClientSocketPool {
       const std::string& group_name,
       const ClientSocketHandle* handle) const OVERRIDE;
 
+  virtual void AddLayeredPool(LayeredPool* layered_pool) OVERRIDE;
+
+  virtual void RemoveLayeredPool(LayeredPool* layered_pool) OVERRIDE;
+
   virtual base::DictionaryValue* GetInfoAsValue(
       const std::string& name,
       const std::string& type,
@@ -225,6 +233,9 @@ class NET_EXPORT_PRIVATE HttpProxyClientSocketPool : public ClientSocketPool {
 
   virtual ClientSocketPoolHistograms* histograms() const OVERRIDE;
 
+  // LayeredPool implementation.
+  virtual bool CloseOneIdleConnection() OVERRIDE;
+
  private:
   typedef ClientSocketPoolBase<HttpProxySocketParams> PoolBase;