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

net/disk_cache/simple/simple_index_file.cc

Index: net/disk_cache/simple/simple_index_file.cc
diff --git a/net/disk_cache/simple/simple_index_file.cc b/net/disk_cache/simple/simple_index_file.cc
index 01eaba1e00cd1ca1753b416e5fa171ca61dc9441..550c5f2ee9a5d4cb30d557c3132e0627151bb12b 100644
--- a/net/disk_cache/simple/simple_index_file.cc
+++ b/net/disk_cache/simple/simple_index_file.cc
@@ -340,11 +340,12 @@ bool SimpleIndexFile::IndexMetadata::CheckIndexMetadata() {
     return false;
   }
 
-  static_assert(kSimpleVersion == 7, "index metadata reader out of date");
+  static_assert(kSimpleVersion == 8, "index metadata reader out of date");
   // No |reason_| is saved in the version 6 file format.
   if (version_ == 6)
     return reason_ == SimpleIndex::INDEX_WRITE_REASON_MAX;
-  return version_ == 7 && reason_ < SimpleIndex::INDEX_WRITE_REASON_MAX;
+  return (version_ == 7 || version_ == 8) &&
+         reason_ < SimpleIndex::INDEX_WRITE_REASON_MAX;
 }
 
 SimpleIndexFile::SimpleIndexFile(
@@ -559,7 +560,8 @@ void SimpleIndexFile::Deserialize(const char* data, int data_len,
     uint64_t hash_key;
     EntryMetadata entry_metadata;
     if (!pickle_it.ReadUInt64(&hash_key) ||
-        !entry_metadata.Deserialize(&pickle_it)) {
+        !entry_metadata.Deserialize(&pickle_it,
+                                    index_metadata.has_memory_entry_data())) {
       LOG(WARNING) << "Invalid EntryMetadata in Simple Index file.";
       entries->clear();
       return;