Fixes the cache lock issue.

net/http/http_network_transaction.cc

Index: net/http/http_network_transaction.cc
diff --git a/net/http/http_network_transaction.cc b/net/http/http_network_transaction.cc
index b7ceb430bd9ea8bc3f1b202cdf7aaf483f3b4976..9fde27c4e0532bc3160c4ef434fb04ed7c86eb19 100644
--- a/net/http/http_network_transaction.cc
+++ b/net/http/http_network_transaction.cc
@@ -288,6 +288,14 @@ bool HttpNetworkTransaction::IsReadyToRestartForAuth() {
       HaveAuth(pending_auth_target_);
 }
 
+void HttpNetworkTransaction::Orphan(std::unique_ptr<HttpTransaction> trans) {
+  // Orphan is needed to allow HttpCache::Transaction to be orphaned for shared
+  // async operations, but it's consumer can also own HttpNetworkTransaction
+  // for specific use cases like proxy script fetching, so it also needs an
+  // implementation here.
+  trans.reset();
+}
+
 int HttpNetworkTransaction::Read(IOBuffer* buf, int buf_len,
                                  const CompletionCallback& callback) {
   DCHECK(buf);