[ios] Creates feedLastRefreshTime perf and FeedWasShown provider method.

- Creates a pref that tracks the last time when the DiscoverFeed
was refreshed. This is now registered using the ContentSuggestions
mediator.

- Adds a new method to the DiscoverFeedProvider that will be called
once the Feed has been shown. This is reported to the Coordinator
using ContentSuggestions audience.


Bug: 1156346
Change-Id: I8333d4c3dd8e372313449815b3aa336315ca5960
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2577886
Commit-Queue: Sergio Collazos <sczs@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#835934}

ios/chrome/browser/pref_names.cc

@@ -80,6 +80,10 @@ const char kIosBookmarkPromoAlreadySeen[] = "ios.bookmark.promo_already_seen";
 const char kIosBookmarkSigninPromoDisplayedCount[] =
     "ios.bookmark.signin_promo_displayed_count";
 
+// The time when the DiscoverFeed was last refreshed.
+const char kIosDiscoverFeedLastRefreshTime[] =
+    "ios.discover_feed.last_refresh_time";
+
 // Preference that hold a boolean indicating if the user has already dismissed
 // the sign-in promo in settings view.
 const char kIosSettingsPromoAlreadySeen[] = "ios.settings.promo_already_seen";

ios/chrome/browser/pref_names.h

@@ -26,6 +26,7 @@ extern const char kIosBookmarkCachedTopMostRow[];
 extern const char kIosBookmarkFolderDefault[];
 extern const char kIosBookmarkPromoAlreadySeen[];
 extern const char kIosBookmarkSigninPromoDisplayedCount[];
+extern const char kIosDiscoverFeedLastRefreshTime[];
 extern const char kIosSettingsPromoAlreadySeen[];
 extern const char kIosSettingsSigninPromoDisplayedCount[];
 extern const char kLastSessionExitedCleanly[];

ios/chrome/browser/prefs/BUILD.gn

@@ -83,6 +83,7 @@ source_set("browser_prefs") {
     "//ios/chrome/browser/ui/authentication",
     "//ios/chrome/browser/ui/bookmarks:constants",
     "//ios/chrome/browser/ui/bookmarks:core",
+    "//ios/chrome/browser/ui/content_suggestions",
     "//ios/chrome/browser/ui/first_run:field_trial",
     "//ios/chrome/browser/ui/incognito_reauth:incognito_reauth_scene_agent",
     "//ios/chrome/browser/voice:prefs",

ios/chrome/browser/prefs/browser_prefs.mm

@@ -66,6 +66,7 @@
 #import "ios/chrome/browser/ui/bookmarks/bookmark_mediator.h"
 #import "ios/chrome/browser/ui/bookmarks/bookmark_path_cache.h"
 #import "ios/chrome/browser/ui/bookmarks/bookmark_utils_ios.h"
+#import "ios/chrome/browser/ui/content_suggestions/content_suggestions_mediator.h"
 #import "ios/chrome/browser/ui/first_run/location_permissions_field_trial.h"
 #import "ios/chrome/browser/ui/incognito_reauth/incognito_reauth_scene_agent.h"
 #include "ios/chrome/browser/voice/voice_search_prefs_registration.h"
@@ -195,6 +196,7 @@ void RegisterBrowserStatePrefs(user_prefs::PrefRegistrySyncable* registry) {
 
   [BookmarkMediator registerBrowserStatePrefs:registry];
   [BookmarkPathCache registerBrowserStatePrefs:registry];
+  [ContentSuggestionsMediator registerBrowserStatePrefs:registry];
   [SigninPromoViewMediator registerBrowserStatePrefs:registry];
   [HandoffManager registerBrowserStatePrefs:registry];
 

ios/chrome/browser/ui/content_suggestions/BUILD.gn

@@ -40,6 +40,7 @@ source_set("content_suggestions") {
     "//components/feed/core/shared_prefs:feed_shared_prefs",
     "//components/ntp_snippets",
     "//components/ntp_tiles",
+    "//components/pref_registry",
     "//components/prefs",
     "//components/prefs/ios",
     "//components/reading_list/core",

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

@@ -124,6 +124,11 @@
 @property(nonatomic, assign) AuthenticationService* authService;
 // Coordinator in charge of handling sharing use cases.
 @property(nonatomic, strong) SharingCoordinator* sharingCoordinator;
+// YES if the feedShown method has already been called.
+// TODO(crbug.com/1126940): The coordinator shouldn't be keeping track of this
+// for its |self.discoverFeedViewController| remove once we have an appropriate
+// callback.
+@property(nonatomic, assign) BOOL feedShownWasCalled;
 
 @end
 
@@ -375,6 +380,13 @@
   _discoverFeedHeaderMenuButton = menuButton;
 }
 
+- (void)discoverFeedShown {
+  if (IsDiscoverFeedEnabled() && !self.feedShownWasCalled) {
+    ios::GetChromeBrowserProvider()->GetDiscoverFeedProvider()->FeedWasShown();
+    self.feedShownWasCalled = YES;
+  }
+}
+
 #pragma mark - OverscrollActionsControllerDelegate
 
 - (void)overscrollActionsController:(OverscrollActionsController*)controller

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

@@ -27,6 +27,10 @@ namespace ntp_tiles {
 class MostVisitedSites;
 }
 
+namespace user_prefs {
+class PrefRegistrySyncable;
+}  // namespace user_prefs
+
 @protocol ContentSuggestionsCommands;
 @protocol ContentSuggestionsConsumer;
 @protocol ContentSuggestionsGestureCommands;
@@ -61,6 +65,9 @@ class ReadingListModel;
 
 - (instancetype)init NS_UNAVAILABLE;
 
+// Registers the feature preferences.
++ (void)registerBrowserStatePrefs:(user_prefs::PrefRegistrySyncable*)registry;
+
 // Command handler for the mediator.
 @property(nonatomic, weak)
     id<ContentSuggestionsCommands, ContentSuggestionsGestureCommands>

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

@@ -14,6 +14,7 @@
 #include "components/ntp_tiles/metrics.h"
 #include "components/ntp_tiles/most_visited_sites.h"
 #include "components/ntp_tiles/ntp_tile.h"
+#import "components/pref_registry/pref_registry_syncable.h"
 #import "components/prefs/ios/pref_observer_bridge.h"
 #include "components/prefs/pref_change_registrar.h"
 #include "components/reading_list/core/reading_list_model.h"
@@ -21,6 +22,7 @@
 #include "ios/chrome/browser/application_context.h"
 #include "ios/chrome/browser/ntp_tiles/most_visited_sites_observer_bridge.h"
 #include "ios/chrome/browser/pref_names.h"
+#import "ios/chrome/browser/pref_names.h"
 #import "ios/chrome/browser/ui/content_suggestions/cells/content_suggestions_discover_item.h"
 #import "ios/chrome/browser/ui/content_suggestions/cells/content_suggestions_item.h"
 #import "ios/chrome/browser/ui/content_suggestions/cells/content_suggestions_learn_more_item.h"
@@ -210,6 +212,10 @@ const NSInteger kMaxNumMostVisitedTiles = 4;
   return self;
 }
 
++ (void)registerBrowserStatePrefs:(user_prefs::PrefRegistrySyncable*)registry {
+  registry->RegisterInt64Pref(prefs::kIosDiscoverFeedLastRefreshTime, 0);
+}
+
 - (void)disconnect {
   _prefChangeRegistrar.reset();
   _prefObserverBridge.reset();

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

@@ -840,6 +840,7 @@ NSString* const kContentSuggestionsMostVisitedAccessibilityIdentifierPrefix =
     // more reliably.
     if (self.feedView.contentSize.height > kDiscoverFeedLoadedHeight) {
       [self.discoverFeedMenuHandler notifyFeedLoadedForHeaderMenu];
+      [self.audience discoverFeedShown];
     }
   }
 }

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

@@ -15,6 +15,11 @@
 // provides a reference to the button.
 - (void)discoverHeaderMenuButtonShown:(UIView*)menuButton;
 
+// Notifies the audience that the Discover Feed has been shown.
+// TODO(crbug.com/1126940): This is still a best effort approach and might be
+// called multiple times.
+- (void)discoverFeedShown;
+
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_CONTENT_SUGGESTIONS_VIEW_CONTROLLER_AUDIENCE_H_

ios/public/provider/chrome/browser/discover_feed/discover_feed_provider.h

@@ -59,6 +59,10 @@ class DiscoverFeedProvider {
   virtual void RemoveObserver(Observer* observer);
   // Loads and appends the next set of articles in the feed.
   virtual void LoadMoreFeedArticles();
+  // Called by the embedder whenever the Feed has been shown.
+  // TODO(crbug.com/1126940): The Feed should have a callback for this, remove
+  // when its available.
+  virtual void FeedWasShown();
 };
 
 #endif  // IOS_PUBLIC_PROVIDER_CHROME_BROWSER_DISCOVER_FEED_DISCOVER_FEED_PROVIDER_H_

ios/public/provider/chrome/browser/discover_feed/discover_feed_provider.mm

@@ -33,3 +33,4 @@ void DiscoverFeedProvider::UpdateFeedForAccountChange() {}
 void DiscoverFeedProvider::AddObserver(Observer* observer) {}
 void DiscoverFeedProvider::RemoveObserver(Observer* observer) {}
 void DiscoverFeedProvider::LoadMoreFeedArticles() {}
+void DiscoverFeedProvider::FeedWasShown() {}