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

net/disk_cache/simple/simple_entry_impl.h

Index: net/disk_cache/simple/simple_entry_impl.h
diff --git a/net/disk_cache/simple/simple_entry_impl.h b/net/disk_cache/simple/simple_entry_impl.h
index 7ab6c38e4ef1bd55d1ba8a60a258dbfee94afca0..e92a85f3d352f2fb28e028d5b10ba58b56110daa 100644
--- a/net/disk_cache/simple/simple_entry_impl.h
+++ b/net/disk_cache/simple/simple_entry_impl.h
@@ -83,8 +83,10 @@ class NET_EXPORT_PRIVATE SimpleEntryImpl : public Entry,
       std::unique_ptr<ActiveEntryProxy> active_entry_proxy);
 
   // Adds another reader/writer to this entry, if possible, returning |this| to
-  // |entry|.
-  int OpenEntry(Entry** entry, const CompletionCallback& callback);
+  // |entry|.  |oracle| is permitted to be a null callback.
+  int OpenEntry(Entry** entry,
+                const Backend::OracleCallback& oracle,
+                const CompletionCallback& callback);
 
   // Creates this entry, if possible. Returns |this| to |entry|.
   int CreateEntry(Entry** entry, const CompletionCallback& callback);
@@ -108,6 +110,7 @@ class NET_EXPORT_PRIVATE SimpleEntryImpl : public Entry,
   base::Time GetLastUsed() const override;
   base::Time GetLastModified() const override;
   int32_t GetDataSize(int index) const override;
+  void SetOracleByte(uint8_t) override;
   int ReadData(int stream_index,
                int offset,
                net::IOBuffer* buf,