[ios] Add IOS.MagicStack.Start/NTP.SegmentationRankingFetchTime

These metrics will measure the fetch time for the Magic Stack
Segmentation ranking to validate hypothesis that Start fetches take
much longer.

Change-Id: I3aa3a9ae83e958768ce831426bc95d86b74e0896
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5530559
Reviewed-by: Guillem Perez <guiperez@google.com>
Commit-Queue: Chris Lu <thegreenfrog@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1299600}

ios/chrome/browser/ui/content_suggestions/content_suggestions_metrics_constants.h

@@ -31,4 +31,9 @@ extern const char kMagicStackModuleEngagementSafetyCheckIndexHistogram[];
 extern const char kMagicStackModuleEngagementParcelTrackingIndexHistogram[];
 extern const char kContentNotificationSnackbarEventHistogram[];
 
+// The name of the histogram that records fetch time for the Segmentation
+// ranking for Magic Stack.
+extern const char kMagicStackStartSegmentationRankingFetchTimeHistogram[];
+extern const char kMagicStackNTPSegmentationRankingFetchTimeHistogram[];
+
 #endif  // IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_CONTENT_SUGGESTIONS_METRICS_CONSTANTS_H_

ios/chrome/browser/ui/content_suggestions/content_suggestions_metrics_constants.mm

@@ -39,3 +39,8 @@ const char kMagicStackModuleEngagementParcelTrackingIndexHistogram[] =
     "IOS.MagicStack.Module.Click.ParcelTracking";
 const char kContentNotificationSnackbarEventHistogram[] =
     "ContentNotifications.Promo.Snackbar.Event";
+
+const char kMagicStackStartSegmentationRankingFetchTimeHistogram[] =
+    "IOS.MagicStack.Start.SegmentationRankingFetchTime";
+const char kMagicStackNTPSegmentationRankingFetchTimeHistogram[] =
+    "IOS.MagicStack.NTP.SegmentationRankingFetchTime";

ios/chrome/browser/ui/content_suggestions/magic_stack/magic_stack_ranking_model.mm

@@ -4,6 +4,7 @@
 
 #import "ios/chrome/browser/ui/content_suggestions/magic_stack/magic_stack_ranking_model.h"
 
+#import "base/metrics/histogram_macros.h"
 #import "components/segmentation_platform/public/constants.h"
 #import "components/segmentation_platform/public/features.h"
 #import "components/segmentation_platform/public/segmentation_platform_service.h"
@@ -19,6 +20,7 @@
 #import "ios/chrome/browser/ui/content_suggestions/cells/shortcuts_mediator.h"
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestions_constants.h"
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestions_consumer.h"
+#import "ios/chrome/browser/ui/content_suggestions/content_suggestions_metrics_constants.h"
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestions_metrics_recorder.h"
 #import "ios/chrome/browser/ui/content_suggestions/magic_stack/magic_stack_ranking_model_delegate.h"
 #import "ios/chrome/browser/ui/content_suggestions/magic_stack/most_visited_tiles_config.h"
@@ -65,6 +67,7 @@
   ParcelTrackingMediator* _parcelTrackingMediator;
   ShortcutsMediator* _shortcutsMediator;
   SafetyCheckMagicStackMediator* _safetyCheckMediator;
+  base::TimeTicks ranking_fetch_start_time_;
 }
 
 - (instancetype)initWithSegmentationService:
@@ -365,6 +368,7 @@
   } else {
     options.on_demand_execution = true;
   }
+  ranking_fetch_start_time_ = base::TimeTicks::Now();
   _segmentationService->GetClassificationResult(
       segmentation_platform::kIosModuleRankerKey, options, inputContext,
       base::BindOnce(
@@ -380,6 +384,14 @@
     return;
   }
 
+  if ([self.homeStartDataSource isStartSurface]) {
+    LOCAL_HISTOGRAM_TIMES(kMagicStackStartSegmentationRankingFetchTimeHistogram,
+                          base::TimeTicks::Now() - ranking_fetch_start_time_);
+  } else {
+    LOCAL_HISTOGRAM_TIMES(kMagicStackNTPSegmentationRankingFetchTimeHistogram,
+                          base::TimeTicks::Now() - ranking_fetch_start_time_);
+  }
+
   NSMutableArray* magicStackOrder = [NSMutableArray array];
   for (const std::string& label : result.ordered_labels) {
     if (label == segmentation_platform::kMostVisitedTiles) {

ios/chrome/browser/ui/content_suggestions/magic_stack/magic_stack_ranking_model_unittest.mm

@@ -37,6 +37,7 @@
 #import "ios/chrome/browser/ui/content_suggestions/cells/shortcuts_mediator.h"
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestions_constants.h"
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestions_consumer.h"
+#import "ios/chrome/browser/ui/content_suggestions/content_suggestions_metrics_constants.h"
 #import "ios/chrome/browser/ui/content_suggestions/content_suggestions_metrics_recorder.h"
 #import "ios/chrome/browser/ui/content_suggestions/magic_stack/magic_stack_ranking_model_delegate.h"
 #import "ios/chrome/browser/ui/content_suggestions/parcel_tracking/parcel_tracking_item.h"
@@ -348,6 +349,8 @@ TEST_F(MagicStackRankingModelTest, TestMagicStackOrderSegmentationServiceCall) {
         return _magicStackRankingModel.hasReceivedMagicStackResponse;
       }));
   EXPECT_OCMOCK_VERIFY(consumer_);
+  histogram_tester_->ExpectTotalCount(
+      kMagicStackNTPSegmentationRankingFetchTimeHistogram, 1);
 }
 
 // Tests that the -setMagicStackOrder: consumer call is executed with the

tools/metrics/histograms/metadata/ios/histograms.xml

@@ -1594,6 +1594,25 @@ the generic promo launch. -->
   </summary>
 </histogram>
 
+<histogram name="IOS.MagicStack.NTP.SegmentationRankingFetchTime" units="ms"
+    expires_after="2024-11-03">
+  <owner>thegreenfrog@chromium.org</owner>
+  <owner>bling-get-set-up@google.com</owner>
+  <summary>
+    Records the fetch time for the Segmentation ranking for Magic Stack on NTP.
+  </summary>
+</histogram>
+
+<histogram name="IOS.MagicStack.Start.SegmentationRankingFetchTime" units="ms"
+    expires_after="2024-11-03">
+  <owner>thegreenfrog@chromium.org</owner>
+  <owner>bling-get-set-up@google.com</owner>
+  <summary>
+    Records the fetch time for the Segmentation ranking for Magic Stack on
+    Start.
+  </summary>
+</histogram>
+
 <histogram name="IOS.MainFrameNavigationIsInBrowserLockdownMode" enum="Boolean"
     expires_after="2024-11-03">
   <owner>joemerramos@chromium.org</owner>