Add specific error codes for when SOCKS connect fails....

net/http/http_network_transaction.cc

Index: net/http/http_network_transaction.cc
===================================================================
--- net/http/http_network_transaction.cc	(revision 38060)
+++ net/http/http_network_transaction.cc	(working copy)
@@ -1585,7 +1585,18 @@
     case ERR_CONNECTION_ABORTED:
     case ERR_TIMED_OUT:
     case ERR_TUNNEL_CONNECTION_FAILED:
+    case ERR_SOCKS_CONNECTION_FAILED:
       break;
+    case ERR_SOCKS_CONNECTION_HOST_UNREACHABLE:
+      // Remap the SOCKS-specific "host unreachable" error to a more
+      // generic error code (This way consumers like the link doctor
+      // can substitute the error page).
+      //
+      // Note that if the host resolving was done by the
+      // SOCSK5 proxy, we can't differentiate between a proxy-side
+      // "host not found" versus a proxy-side "address unreachable" error, and
+      // will report both of these failures as ERR_ADDRESS_UNREACHABLE.
+      return ERR_ADDRESS_UNREACHABLE;
     default:
       return error;
   }