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

net/http/mock_http_cache.h

Index: net/http/mock_http_cache.h
diff --git a/net/http/mock_http_cache.h b/net/http/mock_http_cache.h
index 7718f35116974bb17bda26854341e77f7b93ba5f..49408b075a62a43e546e3a06b7af0ab62e349b16 100644
--- a/net/http/mock_http_cache.h
+++ b/net/http/mock_http_cache.h
@@ -64,6 +64,9 @@ class MockDiskEntry : public disk_cache::Entry,
   void CancelSparseIO() override;
   int ReadyForSparseIO(const CompletionCallback& completion_callback) override;
 
+  uint8_t memory_entry_data() const { return memory_entry_data_; }

[gavinp, 2017/06/26 20:18:11]

Is this implemented here to make sure that http_cache_transaction unit tests
test this path?

Should we provide an implementation that mimics the blockfile cache, and always
returns 0?

+  void set_memory_entry_data(uint8_t val) { memory_entry_data_ = val; }
+
   // Fail most subsequent requests.
   void set_fail_requests() { fail_requests_ = true; }
 
@@ -98,6 +101,7 @@ class MockDiskEntry : public disk_cache::Entry,
 
   std::string key_;
   std::vector<char> data_[kNumCacheEntryDataIndices];
+  unsigned char memory_entry_data_;
   int test_mode_;
   bool doomed_;
   bool sparse_;
@@ -137,6 +141,8 @@ class MockDiskCache : public disk_cache::Backend {
   size_t DumpMemoryStats(
       base::trace_event::ProcessMemoryDump* pmd,
       const std::string& parent_absolute_name) const override;
+  uint8_t GetMemoryEntryData(const std::string& key) override;
+  void SetMemoryEntryData(const std::string& key, uint8_t data) override;
 
   // Returns number of times a cache entry was successfully opened.
   int open_count() const { return open_count_; }