QUIC - histograms to measure the time spent to read QUIC sever

net/quic/crypto/quic_server_info.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_QUIC_CRYPTO_QUIC_SERVER_INFO_H_
 #define NET_QUIC_CRYPTO_QUIC_SERVER_INFO_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 37 matching lines @@
   // doesn't have a pending callback).
   virtual bool IsDataReady() = 0;
 
   // Persist allows for the server information to be updated for future users.
   // This is a fire and forget operation: the caller may drop its reference
   // from this object and the store operation will still complete. This can
   // only be called once WaitForDataReady has returned OK or called its
   // callback.
   virtual void Persist() = 0;
 
+  // Helper methods used for computing time spent to read QUIC server
+  // information from disk cache.
+  const base::TimeTicks& read_start_time() const { return read_start_time_; }
+  void set_read_start_time(const base::TimeTicks& request_time) {
+    read_start_time_ = request_time;
+  }
+
   struct State {
     State();
     ~State();
 
     void Clear();
 
     // This class matches QuicClientCryptoConfig::CachedState.
     std::string server_config;         // A serialized handshake message.
     std::string source_address_token;  // An opaque proof of IP ownership.
     std::vector<std::string> certs;    // A list of certificates in leaf-first
@@ skipping 19 matching lines @@
 
  private:
   // ParseInner is a helper function for Parse.
   bool ParseInner(const std::string& data);
 
   // SerializeInner is a helper function for Serialize.
   std::string SerializeInner() const;
 
   // This is the QUIC server hostname for which we restore the crypto_config.
   const std::string hostname_;
+
+  // Time when call to WaitForDataReady was made, used for computing time spent
+  // to read QUIC server information from disk cache.
+  base::TimeTicks read_start_time_;
 };
 
 class QuicServerInfoFactory {
  public:
   virtual ~QuicServerInfoFactory();
 
   // GetForHost returns a fresh, allocated QuicServerInfo for the given
   // hostname or NULL on failure.
   virtual QuicServerInfo* GetForHost(const std::string& hostname) = 0;
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_CRYPTO_QUIC_SERVER_INFO_H_