Update from https://crrev.com/304121

net/http/disk_cache_based_quic_server_info.h

Index: net/http/disk_cache_based_quic_server_info.h
diff --git a/net/http/disk_cache_based_quic_server_info.h b/net/http/disk_cache_based_quic_server_info.h
index 97fe95e10c79b08da35b84b9fcf8da9c6f75612f..e95d5355c97d27bc8f1bf35eeec31e562f623170 100644
--- a/net/http/disk_cache_based_quic_server_info.h
+++ b/net/http/disk_cache_based_quic_server_info.h
@@ -38,9 +38,11 @@ class NET_EXPORT_PRIVATE DiskCacheBasedQuicServerInfo
   bool IsDataReady() override;
   bool IsReadyToPersist() override;
   void Persist() override;
+  void OnExternalCacheHit() override;
 
  private:
   struct CacheOperationDataShim;
+
   enum State {
     GET_BACKEND,
     GET_BACKEND_COMPLETE,
@@ -57,8 +59,42 @@ class NET_EXPORT_PRIVATE DiskCacheBasedQuicServerInfo
     NONE,
   };
 
+  // Enum to track number of times data read/parse/write API calls of
+  // QuicServerInfo to and from disk cache is called.
+  enum QuicServerInfoAPICall {
+    QUIC_SERVER_INFO_START = 0,
+    QUIC_SERVER_INFO_WAIT_FOR_DATA_READY = 1,
+    QUIC_SERVER_INFO_PARSE = 2,
+    QUIC_SERVER_INFO_WAIT_FOR_DATA_READY_CANCEL = 3,
+    QUIC_SERVER_INFO_READY_TO_PERSIST = 4,
+    QUIC_SERVER_INFO_PERSIST = 5,
+    QUIC_SERVER_INFO_EXTERNAL_CACHE_HIT = 6,
+    QUIC_SERVER_INFO_NUM_OF_API_CALLS = 7,
+  };
+
+  // Enum to track failure reasons to read/load/write of QuicServerInfo to
+  // and from disk cache.
+  enum FailureReason {
+    WAIT_FOR_DATA_READY_INVALID_ARGUMENT_FAILURE = 0,
+    GET_BACKEND_FAILURE = 1,
+    OPEN_FAILURE = 2,
+    CREATE_OR_OPEN_FAILURE = 3,
+    PARSE_NO_DATA_FAILURE = 4,
+    PARSE_FAILURE = 5,
+    READ_FAILURE = 6,
+    READY_TO_PERSIST_FAILURE = 7,
+    PERSIST_NO_BACKEND_FAILURE = 8,
+    WRITE_FAILURE = 9,
+    NO_FAILURE = 10,
+    NUM_OF_FAILURES = 11,
+  };
+
   ~DiskCacheBasedQuicServerInfo() override;
 
+  // Persists |pending_write_data_| if it is not empty, otherwise serializes the
+  // data and pesists it.
+  void PersistInternal();
+
   std::string key() const;
 
   // The |unused| parameter is a small hack so that we can have the
@@ -86,23 +122,39 @@ class NET_EXPORT_PRIVATE DiskCacheBasedQuicServerInfo
   // DoSetDone is the terminal state of the write operation.
   int DoSetDone();
 
+  // Tracks in a histogram the number of times data read/parse/write API calls
+  // of QuicServerInfo to and from disk cache is called.
+  void RecordQuicServerInfoStatus(QuicServerInfoAPICall call);
+
+  // Tracks in a histogram the failure reasons to read/load/write of
+  // QuicServerInfo to and from disk cache. It also saves the |failure| in
+  // |last_failure_|.
+  void RecordQuicServerInfoFailure(FailureReason failure);
+
+  // Tracks in a histogram if |last_failure_| is not NO_FAILURE.
+  void RecordLastFailure();
+
   CacheOperationDataShim* data_shim_;  // Owned by |io_callback_|.
   CompletionCallback io_callback_;
   State state_;
   bool ready_;
   bool found_entry_;  // Controls the behavior of DoCreateOrOpen.
   std::string new_data_;
+  std::string pending_write_data_;
   const QuicServerId server_id_;
   HttpCache* const http_cache_;
   disk_cache::Backend* backend_;
   disk_cache::Entry* entry_;
-  CompletionCallback user_callback_;
+  CompletionCallback wait_for_ready_callback_;
   scoped_refptr<IOBuffer> read_buffer_;
   scoped_refptr<IOBuffer> write_buffer_;
   std::string data_;
   base::TimeTicks load_start_time_;
+  FailureReason last_failure_;
 
   base::WeakPtrFactory<DiskCacheBasedQuicServerInfo> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(DiskCacheBasedQuicServerInfo);
 };
 
 }  // namespace net