Add Finch experiment for selectively bypassing proxies.

net/socket_stream/socket_stream.cc

Index: net/socket_stream/socket_stream.cc
diff --git a/net/socket_stream/socket_stream.cc b/net/socket_stream/socket_stream.cc
index 7404ff34a4c4b658041026ef5db5b2758138e8ab..85a19ef28359bcc1eb2712da9fd3ddda74334774 100644
--- a/net/socket_stream/socket_stream.cc
+++ b/net/socket_stream/socket_stream.cc
@@ -630,7 +630,7 @@ int SocketStream::DoResolveProxy() {
   // Alternate-Protocol header here for ws:// or TLS NPN extension for wss:// .
 
   return context_->proxy_service()->ResolveProxy(
-      proxy_url_, &proxy_info_, io_callback_, &pac_request_, net_log_);
+      proxy_url_, 0, &proxy_info_, io_callback_, &pac_request_, net_log_);
 }
 
 int SocketStream::DoResolveProxyComplete(int result) {