Fixes the cache lock issue.

net/http/http_cache_lookup_manager.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/http/http_cache_lookup_manager.h"
 
 #include "net/base/load_flags.h"
 
 namespace net {
 
 HttpCacheLookupManager::LookupTransaction::LookupTransaction(
     std::unique_ptr<ServerPushHelper> server_push_helper)
     : push_helper_(std::move(server_push_helper)),
       request_(new HttpRequestInfo()),
       transaction_(nullptr) {}
 
-HttpCacheLookupManager::LookupTransaction::~LookupTransaction() {}
+HttpCacheLookupManager::LookupTransaction::~LookupTransaction() {
+  transaction_->Orphan(std::move(transaction_));
+}
 
 int HttpCacheLookupManager::LookupTransaction::StartLookup(
     HttpCache* cache,
     const CompletionCallback& callback,
     const NetLogWithSource& net_log) {
   request_->url = push_helper_->GetURL();
   request_->method = "GET";
   request_->load_flags = LOAD_ONLY_FROM_CACHE | LOAD_SKIP_CACHE_VALIDATION;
   cache->CreateTransaction(DEFAULT_PRIORITY, &transaction_);
   return transaction_->Start(request_.get(), callback, net_log);
@@ skipping 33 matching lines @@
   auto it = lookup_transactions_.find(url);
   DCHECK(it != lookup_transactions_.end());
 
   if (rv == OK)
     it->second->CancelPush();
 
   lookup_transactions_.erase(it);
 }
 
 }  // namespace net