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

net/http/mock_http_cache.cc

Index: net/http/mock_http_cache.cc
diff --git a/net/http/mock_http_cache.cc b/net/http/mock_http_cache.cc
index 47125a30cc53f4bdf2969ae35e1c5b607c2706c4..1800fbdaa69e18bcfaa7403f0602d8d1fded904c 100644
--- a/net/http/mock_http_cache.cc
+++ b/net/http/mock_http_cache.cc
@@ -68,6 +68,7 @@ struct MockDiskEntry::CallbackInfo {
 
 MockDiskEntry::MockDiskEntry(const std::string& key)
     : key_(key),
+      oracle_byte_(0),
       doomed_(false),
       sparse_(false),
       fail_requests_(false),
@@ -98,6 +99,10 @@ base::Time MockDiskEntry::GetLastModified() const {
   return base::Time::Now();
 }
 
+void MockDiskEntry::SetOracleByte(uint8_t val) {
+  oracle_byte_ = val;
+}
+
 int32_t MockDiskEntry::GetDataSize(int index) const {
   DCHECK(index >= 0 && index < kNumCacheEntryDataIndices);
   return static_cast<int32_t>(data_[index].size());
@@ -390,6 +395,13 @@ int32_t MockDiskCache::GetEntryCount() const {
 int MockDiskCache::OpenEntry(const std::string& key,
                              disk_cache::Entry** entry,
                              const CompletionCallback& callback) {
+  return OpenEntryWithOracleByte(key, entry, OracleCallback(), callback);
+}
+
+int MockDiskCache::OpenEntryWithOracleByte(const std::string& key,
+                                           disk_cache::Entry** entry,
+                                           const OracleCallback& oracle,
+                                           const CompletionCallback& callback) {
   DCHECK(!callback.is_null());
   if (fail_requests_)
     return ERR_CACHE_OPEN_FAILURE;
@@ -398,6 +410,12 @@ int MockDiskCache::OpenEntry(const std::string& key,
   if (it == entries_.end())
     return ERR_CACHE_OPEN_FAILURE;
 
+  if (!oracle.is_null() && oracle.Run(it->second->GetOracleByte()) ==
+                               Backend::OracleJudgement::MISS_AND_DOOM) {
+    it->second->Doom();
+    // Will be handled immediately below.
+  }
+
   if (it->second->is_doomed()) {
     it->second->Release();
     entries_.erase(it);