[iOS] Show IPH bubble for Discover feed in right position

Corrects the location for the Discover feed header menu IPH bubble by
using the view instead of the button's frame. Adds an event for when
the Discover feed is loaded in order to add a server-side config for
the IPH.

Bug: 1124448, 1085419
Change-Id: I4df2919e428a5cdc429b6b157a34b82f80e3421b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2401971Reviewed-by: Tommy Nyquist <nyquist@chromium.org>
Reviewed-by: Sergio Collazos <sczs@chromium.org>
Commit-Queue: Adam Trudeau-Arcaro <adamta@google.com>
Cr-Commit-Position: refs/heads/master@{#805914}

components/feature_engagement/public/event_constants.cc

@@ -42,6 +42,7 @@ const char kClearedBrowsingData[] = "cleared_browsing_data";
 const char kViewedReadingList[] = "viewed_reading_list";
 const char kTriggeredTranslateInfobar[] = "triggered_translate_infobar";
 const char kBottomToolbarOpened[] = "bottom_toolbar_opened";
+const char kDiscoverFeedLoaded[] = "discover_feed_loaded";
 #endif  // defined(OS_IOS)
 
 }  // namespace events

components/feature_engagement/public/event_constants.h

@@ -75,6 +75,9 @@ extern const char kTriggeredTranslateInfobar[];
 
 // The user has viewed the the BottomToolbar tip.
 extern const char kBottomToolbarOpened[];
+
+// The Discover feed has loaded content in the NTP.
+extern const char kDiscoverFeedLoaded[];
 #endif  // defined(OS_IOS)
 
 }  // namespace events

ios/chrome/browser/ui/bubble/bubble_presenter.mm

@@ -271,9 +271,14 @@ presentBubbleForFeature:(const base::Feature&)feature
   BubbleArrowDirection arrowDirection = BubbleArrowDirectionDown;
   NSString* text =
       l10n_util::GetNSStringWithFixup(IDS_IOS_DISCOVER_FEED_HEADER_IPH);
+
+  NamedGuide* guide = [NamedGuide guideWithName:kDiscoverFeedHeaderMenuGuide
+                                           view:self.rootViewController.view];
+  DCHECK(guide);
+  UIView* menuButton = guide.constrainedView;
   CGPoint discoverFeedHeaderAnchor =
-      [self anchorPointToGuide:kDiscoverFeedHeaderMenuGuide
-                     direction:arrowDirection];
+      [menuButton.superview convertPoint:menuButton.frame.origin toView:nil];
+  discoverFeedHeaderAnchor.x += menuButton.frame.size.width / 2;
 
   // If the feature engagement tracker does not consider it valid to display
   // the new tab tip, then end early to prevent the potential reassignment

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

@@ -37,6 +37,7 @@ source_set("content_suggestions") {
     ":feature_flags",
     "//base",
     "//components/favicon/core",
+    "//components/feature_engagement/public",
     "//components/feed/core/shared_prefs:feed_shared_prefs",
     "//components/ntp_snippets",
     "//components/ntp_tiles",
@@ -54,6 +55,7 @@ source_set("content_suggestions") {
     "//ios/chrome/browser/discover_feed",
     "//ios/chrome/browser/drag_and_drop",
     "//ios/chrome/browser/favicon",
+    "//ios/chrome/browser/feature_engagement",
     "//ios/chrome/browser/main:public",
     "//ios/chrome/browser/metrics:metrics_internal",
     "//ios/chrome/browser/ntp",

ios/chrome/browser/ui/content_suggestions/cells/content_suggestions_discover_header_item.mm

@@ -176,8 +176,7 @@ const CGFloat kFeedCardIPhoneWidth = 375;
       [NamedGuide guideWithName:kDiscoverFeedHeaderMenuGuide
                            view:self.menuButton];
 
-  menuButtonGuide.constrainedFrame =
-      [self.contentView convertRect:self.menuButton.frame toView:nil];
+  menuButtonGuide.constrainedView = self.menuButton;
   self.discoverFeedVisible = [NSNumber numberWithBool:visible];
 }
 

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

@@ -8,6 +8,8 @@
 #include "base/metrics/user_metrics.h"
 #include "base/metrics/user_metrics_action.h"
 #include "base/scoped_observer.h"
+#import "components/feature_engagement/public/event_constants.h"
+#import "components/feature_engagement/public/tracker.h"
 #include "components/feed/core/shared_prefs/pref_names.h"
 #include "components/ntp_snippets/content_suggestions_service.h"
 #include "components/ntp_snippets/pref_names.h"
@@ -23,6 +25,7 @@
 #include "ios/chrome/browser/favicon/ios_chrome_large_icon_cache_factory.h"
 #include "ios/chrome/browser/favicon/ios_chrome_large_icon_service_factory.h"
 #include "ios/chrome/browser/favicon/large_icon_cache.h"
+#import "ios/chrome/browser/feature_engagement/tracker_factory.h"
 #import "ios/chrome/browser/main/browser.h"
 #include "ios/chrome/browser/ntp_snippets/ios_chrome_content_suggestions_service_factory.h"
 #include "ios/chrome/browser/ntp_tiles/ios_most_visited_sites_factory.h"
@@ -479,6 +482,12 @@
   [self.alertCoordinator start];
 }
 
+- (void)notifyFeedLoadedForHeaderMenu {
+  feature_engagement::TrackerFactory::GetForBrowserState(
+      self.browser->GetBrowserState())
+      ->NotifyEvent(feature_engagement::events::kDiscoverFeedLoaded);
+}
+
 #pragma mark - DiscoverFeedDelegate
 
 - (void)recreateDiscoverFeedViewController {

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

@@ -55,6 +55,9 @@ const CGFloat kDiscoverFeedContentWith = 430;
 const CGFloat kPaginationOffset = 400;
 // Height for the Discover Feed section header.
 const CGFloat kDiscoverFeedFeaderHeight = 30;
+// Minimum height of the Discover feed content to indicate that the articles
+// have loaded.
+const CGFloat kDiscoverFeedLoadedHeight = 1000;
 }
 
 NSString* const kContentSuggestionsMostVisitedAccessibilityIdentifierPrefix =
@@ -816,6 +819,12 @@ NSString* const kContentSuggestionsMostVisitedAccessibilityIdentifierPrefix =
   if (object == self.feedView && [keyPath isEqualToString:@"contentSize"]) {
     // Reload the CollectionView data to adjust to the new Feed height.
     [self.collectionView reloadData];
+    // Indicates that the feed articles have been loaded by checking its height.
+    // TODO(crbug.com/1126940): Use a callback from Mulder to determine this
+    // more reliably.
+    if (self.feedView.contentSize.height > kDiscoverFeedLoadedHeight) {
+      [self.discoverFeedMenuHandler notifyFeedLoadedForHeaderMenu];
+    }
   }
 }
 

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

@@ -11,6 +11,10 @@
 // Opens Discover feed control menu.
 - (void)openDiscoverFeedMenu:(UIView*)menuButton;
 
+// Sends a notification to indicate that the Discover feed has loaded, so the
+// IPH can be shown.
+- (void)notifyFeedLoadedForHeaderMenu;
+
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_DISCOVER_FEED_MENU_COMMANDS_H_