BackoffEntry is used to compute timeouts between consecutive captive portal checks.

chrome/browser/chromeos/net/network_portal_detector_impl.h

Index: chrome/browser/chromeos/net/network_portal_detector_impl.h
diff --git a/chrome/browser/chromeos/net/network_portal_detector_impl.h b/chrome/browser/chromeos/net/network_portal_detector_impl.h
index 53125534e7bf6a9cdf35a33a65a7c716c5c8d632..7573c806d81144fdac89fefa1bf9c464a51f5738 100644
--- a/chrome/browser/chromeos/net/network_portal_detector_impl.h
+++ b/chrome/browser/chromeos/net/network_portal_detector_impl.h
@@ -82,7 +82,7 @@ class NetworkPortalDetectorImpl
   virtual void DefaultNetworkChanged(const NetworkState* network) OVERRIDE;
 
   // PortalDetectorStrategy::Delegate implementation:
-  virtual int AttemptCount() OVERRIDE;
+  virtual uint64 NoResponseResultCount() OVERRIDE;
   virtual base::TimeTicks AttemptStartTime() OVERRIDE;
   virtual base::TimeTicks GetCurrentTimeTicks() OVERRIDE;
 
@@ -126,12 +126,7 @@ class NetworkPortalDetectorImpl
   // Stops whole detection process.
   void StopDetection();
 
-  // Internal predicate which describes set of states from which
-  // DetectCaptivePortal() can be called.
-  bool CanPerformAttempt() const;
-
   // Initiates Captive Portal detection attempt after |delay|.
-  // You should check CanPerformAttempt() before calling this method.
   void ScheduleAttempt(const base::TimeDelta& delay);
 
   // Starts detection attempt.
@@ -170,12 +165,16 @@ class NetworkPortalDetectorImpl
     return state_ == STATE_CHECKING_FOR_PORTAL;
   }
 
-  int attempt_count_for_testing() {
-    return attempt_count_;
+  uint64 same_detection_result_count_for_testing() const {
+    return same_detection_result_count_;
+  }
+
+  uint64 no_response_result_count_for_testing() const {

[antrim, 2014/07/10 13:53:13]

What is the reason for using uint64 instead of int here?

[ygorshenin1, 2014/07/11 11:46:12]

Due to errors or something else int can overflow which leads to undefined
behavior in C++. So I'd prefer to use unsigned integers for monotonic counters.
uint64 is used here instead of uint32 just for safety.

On 2014/07/10 13:53:13, antrim wrote:

+    return no_response_result_count_;
   }
 
-  void set_attempt_count_for_testing(int attempt_count) {
-    attempt_count_ = attempt_count;
+  void set_no_response_result_count_for_testing(uint64 count) {
+    no_response_result_count_ = count;
   }
 
   // Returns delay before next portal check. Used by unit tests.
@@ -192,6 +191,10 @@ class NetworkPortalDetectorImpl
   void RecordDetectionStats(const NetworkState* network,
                             CaptivePortalStatus status);
 
+  // Resets strategy and all counters used in computations of
+  // timeouts.
+  void ResetStrategyAndCounters();
+
   // Sets current test time ticks. Used by unit tests.
   void set_time_ticks_for_testing(const base::TimeTicks& time_ticks) {
     time_ticks_for_testing_ = time_ticks;
@@ -236,15 +239,21 @@ class NetworkPortalDetectorImpl
   // Start time of detection attempt.
   base::TimeTicks attempt_start_time_;
 
-  // Number of already performed detection attempts.
-  int attempt_count_;
-
   // Delay before next portal detection.
   base::TimeDelta next_attempt_delay_;
 
   // Current detection strategy.
   scoped_ptr<PortalDetectorStrategy> strategy_;
 
+  // Last received result from captive portal detector.
+  CaptivePortalStatus last_detection_result_;
+
+  // Number of detection attempts with same result in a row.
+  uint64 same_detection_result_count_;
+
+  // Number of detection attempts in a row with NO RESPONSE result.
+  uint64 no_response_result_count_;
+
   // UI notification controller about captive portal state.
   NetworkPortalNotificationController notification_controller_;