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

net/disk_cache/memory/mem_backend_impl.h

Index: net/disk_cache/memory/mem_backend_impl.h
diff --git a/net/disk_cache/memory/mem_backend_impl.h b/net/disk_cache/memory/mem_backend_impl.h
index 44937a0d54fe2eb1711a5d7d5232991916203b7e..cf8c998e5c9c3e762e22eadc6da3351365037823 100644
--- a/net/disk_cache/memory/mem_backend_impl.h
+++ b/net/disk_cache/memory/mem_backend_impl.h
@@ -73,6 +73,10 @@ class NET_EXPORT_PRIVATE MemBackendImpl final : public Backend {
   // determine if eviction is neccessary and when eviction is finished.
   void ModifyStorageSize(int32_t delta);
 
+  // Returns true if the cache's size is greater than the maximum allowed
+  // size.
+  bool HasExceededStorageSize() const;
+
   // Backend interface.
   net::CacheType GetCacheType() const override;
   int32_t GetEntryCount() const override;