[ios] Adds notice card and network duration fetch to feed metrics recorder

The first one will be used to record notice card (or lack of) impressions,
and the second one to record the time it takes to fetch articles.

Bug: 1145379
Change-Id: I481e86dea3f47d5db8364d87092393bcbcdd00d1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2551851
Commit-Queue: Sergio Collazos <sczs@chromium.org>
Reviewed-by: Adam Trudeau-Arcaro <adamta@google.com>
Cr-Commit-Position: refs/heads/master@{#830261}

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

@@ -83,6 +83,14 @@
 // Records an unknown |commandID| performed by the Feed.
 - (void)recordCommandID:(int)commandID;
 
+// Records if a notice card was presented at the time the feed was initially
+// loaded. e.g. Launch time, user refreshes, and acccount switches.
+- (void)recordNoticeCardShown:(BOOL)shown;
+
+// Records the |durationInSeconds| it took to Discover feed to Fetch articles.
+- (void)recordFeedArticlesFetchDurationInSeconds:
+    (NSTimeInterval)durationInSeconds;
+
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_DISCOVER_FEED_METRICS_RECORDER_H_

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

@@ -107,6 +107,14 @@ const char kDiscoverFeedUserActionInfiniteFeedTriggered[] =
 const char kDiscoverFeedEngagementTypeHistogram[] =
     "ContentSuggestions.Feed.EngagementType";
 
+// Histogram name to capture Feed Notice card impressions.
+const char kDiscoverFeedNoticeCardFulfilled[] =
+    "ContentSuggestions.Feed.NoticeCardFulfilled2";
+
+// Histogram name to measure the time it tood the Feed to fetch articles.
+const char kDiscoverFeedArticlesFetchNetworkDuration[] =
+    "ContentSuggestions.Feed.Network.Duration";
+
 // Minimum scrolling amount to record a FeedEngagementType::kFeedEngaged due to
 // scrolling.
 const int kMinScrollThreshold = 160;
@@ -279,6 +287,16 @@ const int kMinutesBetweenSessions = 5;
   base::UmaHistogramSparse(kDiscoverFeedUserActionCommandHistogram, commandID);
 }
 
+- (void)recordNoticeCardShown:(BOOL)shown {
+  base::UmaHistogramBoolean(kDiscoverFeedNoticeCardFulfilled, shown);
+}
+
+- (void)recordFeedArticlesFetchDurationInSeconds:
+    (NSTimeInterval)durationInSeconds {
+  UMA_HISTOGRAM_MEDIUM_TIMES(kDiscoverFeedArticlesFetchNetworkDuration,
+                             base::TimeDelta::FromSeconds(durationInSeconds));
+}
+
 #pragma mark - Private
 
 // Records histogram metrics for Discover feed user actions.