[net/http auth] Make HttpAuthHandler challenge handling asynchronous.

net/http/http_proxy_client_socket.h

Index: net/http/http_proxy_client_socket.h
diff --git a/net/http/http_proxy_client_socket.h b/net/http/http_proxy_client_socket.h
index 439278aa39853f9a4fcf2756b120aaaba5262b3f..d7836a69048e5f6b3bc0588e39b523e497183428 100644
--- a/net/http/http_proxy_client_socket.h
+++ b/net/http/http_proxy_client_socket.h
@@ -97,6 +97,8 @@ class HttpProxyClientSocket : public ProxyClientSocket {
     STATE_SEND_REQUEST_COMPLETE,
     STATE_READ_HEADERS,
     STATE_READ_HEADERS_COMPLETE,
+    STATE_HANDLE_PROXY_AUTH_CHALLENGE,
+    STATE_HANDLE_PROXY_AUTH_CHALLENGE_COMPLETE,
     STATE_DRAIN_BODY,
     STATE_DRAIN_BODY_COMPLETE,
     STATE_TCP_RESTART,
@@ -124,6 +126,8 @@ class HttpProxyClientSocket : public ProxyClientSocket {
   int DoSendRequestComplete(int result);
   int DoReadHeaders();
   int DoReadHeadersComplete(int result);
+  int DoHandleProxyAuthChallenge();
+  int DoHandleProxyAuthChallengeComplete(int result);
   int DoDrainBody();
   int DoDrainBodyComplete(int result);
   int DoTCPRestart();