RFC: use some in-memory state in SimpleCache to quickly cache-miss some CantConditionalize cases

net/http/http_cache.cc

 // Copyright (c) 2012 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.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 721 matching lines @@
         pending_ops_.erase(it);
         break;
       }
     }
   }
   DCHECK(pending_op->pending_queue.empty());
 
   delete pending_op;
 }
 
-int HttpCache::OpenEntry(const std::string& key, ActiveEntry** entry,
+int HttpCache::OpenEntry(const std::string& key,
+                         ActiveEntry** entry,
                          Transaction* trans) {
   ActiveEntry* active_entry = FindActiveEntry(key);
   if (active_entry) {
     *entry = active_entry;
     return OK;
   }
 
+  // See if we could potentially quick-reject the entry.
+  uint8_t in_memory_info = disk_cache_->GetMemoryEntryData(key);
+  if (trans->MaybeRejectBasedOnMemoryEntryData(in_memory_info)) {
+    return net::OK;  // ERR_FAILED;
+  }
+
   std::unique_ptr<WorkItem> item =
       base::MakeUnique<WorkItem>(WI_OPEN_ENTRY, trans, entry);
   PendingOp* pending_op = GetPendingOp(key);
   if (pending_op->writer) {
     pending_op->pending_queue.push_back(std::move(item));
     return ERR_IO_PENDING;
   }
 
   DCHECK(pending_op->pending_queue.empty());
 
@@ skipping 603 matching lines @@
     building_backend_ = false;
     DeletePendingOp(pending_op);
   }
 
   // The cache may be gone when we return from the callback.
   if (!item->DoCallback(result, disk_cache_.get()))
     item->NotifyTransaction(result, NULL);
 }
 
 }  // namespace net