[ios] Add finch params for Foreground Refresh

Bug: 1418430
Change-Id: I5a7680c22c6fb0af345d39bb23ee691c42fee08e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4300422
Reviewed-by: Sergio Collazos <sczs@chromium.org>
Commit-Queue: edchin <edchin@google.com>
Cr-Commit-Position: refs/heads/main@{#1111983}

ios/chrome/browser/ntp/features.h

@@ -72,6 +72,18 @@ extern const char kEnableFeedRefreshPostFeedSession[];
 // backgrounding.
 extern const char kEnableFeedRefreshOnAppBackgrounding[];
 
+// Feature param under `kEnableFeedForegroundRefresh` for the time interval used
+// to set the session end timer.
+extern const char kFeedSessionEndTimerTimeoutInSeconds[];
+
+// Feature param under `kEnableFeedForegroundRefresh` for the refresh threshold
+// when the last refresh was seen.
+extern const char kFeedSeenRefreshThresholdInSeconds[];
+
+// Feature param under `kEnableFeedForegroundRefresh` for the refresh threshold
+// when the last refresh was unseen.
+extern const char kFeedUnseenRefreshThresholdInSeconds[];
+
 // Whether the Following Feed is enabled on NTP.
 bool IsWebChannelsEnabled();
 
@@ -135,6 +147,16 @@ bool IsFeedRefreshPostFeedSessionEnabled();
 // different from background refresh.
 bool IsFeedRefreshOnAppBackgroundingEnabled();
 
+// Returns the time interval used to set the session end timer.
+double GetFeedSessionEndTimerTimeoutInSeconds();
+
+// Returns the refresh threshold (aka feed expiration) for a feed that has been
+// seen.
+double GetFeedSeenRefreshThresholdInSeconds();
+
+// Returns the refresh threshold (aka feed expiration) for an unseen feed.
+double GetFeedUnseenRefreshThresholdInSeconds();
+
 // YES if enabled Feed bottom sign-in promo.
 bool IsFeedBottomSignInPromoEnabled();
 

ios/chrome/browser/ntp/features.mm

@@ -78,6 +78,12 @@
     "EnableFeedRefreshPostFeedSession";
 const char kEnableFeedRefreshOnAppBackgrounding[] =
     "EnableFeedRefreshOnAppBackgrounding";
+const char kFeedSessionEndTimerTimeoutInSeconds[] =
+    "FeedSessionEndTimerTimeoutInSeconds";
+const char kFeedSeenRefreshThresholdInSeconds[] =
+    "FeedSeenRefreshThresholdInSeconds";
+const char kFeedUnseenRefreshThresholdInSeconds[] =
+    "FeedUnseenRefreshThresholdInSeconds";
 
 bool IsWebChannelsEnabled() {
   return base::FeatureList::IsEnabled(kEnableWebChannels);
@@ -204,6 +210,39 @@ bool IsFeedRefreshOnAppBackgroundingEnabled() {
       /*default=*/false);
 }
 
+double GetFeedSessionEndTimerTimeoutInSeconds() {
+  double override_value = [[NSUserDefaults standardUserDefaults]
+      doubleForKey:@"FeedSessionEndTimerTimeoutInSeconds"];
+  if (override_value > 0.0) {
+    return override_value;
+  }
+  return base::GetFieldTrialParamByFeatureAsDouble(
+      kEnableFeedForegroundRefresh, kFeedSessionEndTimerTimeoutInSeconds,
+      /*default=*/base::Minutes(5).InSecondsF());
+}
+
+double GetFeedSeenRefreshThresholdInSeconds() {
+  double override_value = [[NSUserDefaults standardUserDefaults]
+      doubleForKey:@"FeedSeenRefreshThresholdInSeconds"];
+  if (override_value > 0.0) {
+    return override_value;
+  }
+  return base::GetFieldTrialParamByFeatureAsDouble(
+      kEnableFeedForegroundRefresh, kFeedSeenRefreshThresholdInSeconds,
+      /*default=*/base::Hours(1).InSecondsF());
+}
+
+double GetFeedUnseenRefreshThresholdInSeconds() {
+  double override_value = [[NSUserDefaults standardUserDefaults]
+      doubleForKey:@"FeedUnseenRefreshThresholdInSeconds"];
+  if (override_value > 0.0) {
+    return override_value;
+  }
+  return base::GetFieldTrialParamByFeatureAsDouble(
+      kEnableFeedForegroundRefresh, kFeedUnseenRefreshThresholdInSeconds,
+      /*default=*/base::Hours(6).InSecondsF());
+}
+
 bool IsFeedBottomSignInPromoEnabled() {
   return base::FeatureList::IsEnabled(kEnableFeedBottomSignInPromo);
 }

ios/chrome/browser/ui/ntp/metrics/feed_metrics_recorder.mm

@@ -71,7 +71,7 @@ @interface FeedMetricsRecorder ()
 @property(nonatomic, assign) NSTimeInterval discoverPreviousTimeInFeedGV;
 @property(nonatomic, assign) NSTimeInterval followingPreviousTimeInFeedGV;
 
-// Timer to signal end of session. Set for `kMinutesBetweenSessions`.
+// Timer to signal end of session.
 @property(nonatomic, strong) NSTimer* sessionEndTimer;
 
 @end
@@ -1191,18 +1191,17 @@ - (void)recordOpenURL {
   }
 }
 
-// Sets or extends the session end timer by `kMinutesBetweenSessions`.
+// Sets or extends the session end timer.
 - (void)setOrExtendSessionEndTimer {
   [self.sessionEndTimer invalidate];
   __weak FeedMetricsRecorder* weakSelf = self;
-  self.sessionEndTimer =
-      [NSTimer scheduledTimerWithTimeInterval:kMinutesBetweenSessions *
-                                              60 /*seconds per minute*/
-                                       target:weakSelf
-                                     selector:@selector
-                                     (refreshFeedIfSessionConditionsAreMet)
-                                     userInfo:nil
-                                      repeats:NO];
+  self.sessionEndTimer = [NSTimer
+      scheduledTimerWithTimeInterval:GetFeedSessionEndTimerTimeoutInSeconds()
+                              target:weakSelf
+                            selector:@selector
+                            (refreshFeedIfSessionConditionsAreMet)
+                            userInfo:nil
+                             repeats:NO];
 }
 
 // Refresh the feed if session conditions are met. See implementation for which