[HTTP Cache] Prevent memory backend from exceeding its max size

net/disk_cache/memory/mem_backend_impl.cc

Index: net/disk_cache/memory/mem_backend_impl.cc
diff --git a/net/disk_cache/memory/mem_backend_impl.cc b/net/disk_cache/memory/mem_backend_impl.cc
index a7ad28b8d8d1e163aae095faa569e119e91bb864..e6de26f05de0a818c429ec1c68bc41115a8e8667 100644
--- a/net/disk_cache/memory/mem_backend_impl.cc
+++ b/net/disk_cache/memory/mem_backend_impl.cc
@@ -48,7 +48,7 @@ MemBackendImpl::~MemBackendImpl() {
   DCHECK(CheckLRUListOrder(lru_list_));
   while (!entries_.empty())
     entries_.begin()->second->Doom();
-  DCHECK(!current_size_);
+  DCHECK_EQ(0, current_size_);

[jkarlin, 2017/03/30 15:04:42]

Hmm. I'm skeptical that this DCHECK even makes sense. Doomed entries can  live
beyond the backend and current_size_ isn't decremented until the doomed entry is
deleted.

[Randy Smith (Not in Mondays), 2017/03/30 16:38:11]

Plausible skepticism.  I'd say not your problem, though.

[jkarlin, 2017/03/30 17:18:27]

Acknowledged.

 }
 
 // static
@@ -128,6 +128,10 @@ void MemBackendImpl::ModifyStorageSize(int32_t delta) {
     EvictIfNeeded();
 }
 
+bool MemBackendImpl::HasExceededStorageSize() const {
+  return current_size_ > max_size_;
+}
+
 net::CacheType MemBackendImpl::GetCacheType() const {
   return net::MEMORY_CACHE;
 }