[iOS] Add flag to control feed header parameters

Adds feature flag with 3 parameters to control the feed header.
1. Allows us to disable sticky feed header
2. Allows us to control feed header height
3. Moves the unread content dot feature within this flag

(cherry picked from commit f2b2244)

Bug: 1404737
Change-Id: I882c2ac71c90d727f59b165ae67b367b3f495ba4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4131175
Reviewed-by: Sergio Collazos <sczs@chromium.org>
Commit-Queue: Adam Arcaro <adamta@google.com>
Cr-Original-Commit-Position: refs/heads/main@{#1088310}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4134891
Auto-Submit: Adam Arcaro <adamta@google.com>
Commit-Queue: Sergio Collazos <sczs@chromium.org>
Cr-Commit-Position: refs/branch-heads/5481@{#129}
Cr-Branched-From: 130f3e4-refs/heads/main@{#1084008}

ios/chrome/browser/ui/ntp/feed_header_view_controller.mm

@@ -45,8 +45,6 @@
 const CGFloat kHeaderMenuButtonInsetTopAndBottom = 2;
 const CGFloat kHeaderMenuButtonInsetSides = 2;
 // The height of the header container. The content is unaffected.
-// TODO(crbug.com/1277504): Only keep the WC header after launch.
-const CGFloat kWebChannelsHeaderHeight = 52;
 const CGFloat kDiscoverFeedHeaderHeight = 40;
 const CGFloat kCustomSearchEngineLabelHeight = 18;
 // * Values below are exclusive to Web Channels.
@@ -214,7 +212,7 @@ - (void)toggleBackgroundBlur:(BOOL)blurred animated:(BOOL)animated {
 
 - (CGFloat)feedHeaderHeight {
   return [self.feedControlDelegate isFollowingFeedAvailable]
-             ? kWebChannelsHeaderHeight
+             ? FollowingFeedHeaderHeight()
              : kDiscoverFeedHeaderHeight;
 }
 

ios/chrome/browser/ui/ntp/new_tab_page_coordinator.mm

@@ -100,13 +100,6 @@
 #error "This file requires ARC support."
 #endif
 
-namespace {
-// Flag to enable the checking of new content for the Follow Feed.
-BASE_FEATURE(kEnableCheckForNewFollowContent,
-             "EnableCheckForNewFollowContent",
-             base::FEATURE_DISABLED_BY_DEFAULT);
-}  // namespace
-
 @interface NewTabPageCoordinator () <AppStateObserver,
                                      BooleanObserver,
                                      ContentSuggestionsHeaderCommands,
@@ -423,7 +416,7 @@ - (void)constrainDiscoverHeaderMenuButtonNamedGuide {
 
 - (void)updateFollowingFeedHasUnseenContent:(BOOL)hasUnseenContent {
   if (![self isFollowingFeedAvailable] ||
-      !base::FeatureList::IsEnabled(kEnableCheckForNewFollowContent)) {
+      !IsDotEnabledForNewFollowedContent()) {
     return;
   }
   if ([self doesFollowingFeedHaveContent]) {
@@ -885,7 +878,7 @@ - (void)handleFeedSelected:(FeedType)feedType {
   // Saves scroll position before changing feed.
   CGFloat scrollPosition = [self.ntpViewController scrollPosition];
 
-  if (feedType == FeedTypeFollowing) {
+  if (feedType == FeedTypeFollowing && IsDotEnabledForNewFollowedContent()) {
     // Clears dot and notifies service that the Following feed content has
     // been seen.
     [self.feedHeaderViewController
@@ -1006,7 +999,8 @@ - (void)reloadContentSuggestions {
 }
 
 - (BOOL)isContentHeaderSticky {
-  return [self isFollowingFeedAvailable] && [self isFeedHeaderVisible];
+  return [self isFollowingFeedAvailable] && [self isFeedHeaderVisible] &&
+         !IsStickyHeaderDisabledForFollowingFeed();
 }
 
 - (void)signinPromoHasChangedVisibility:(BOOL)visible {
@@ -1495,8 +1489,7 @@ - (FeedHeaderViewController*)feedHeaderViewController {
   DCHECK(!self.browser->GetBrowserState()->IsOffTheRecord());
   if (!_feedHeaderViewController) {
     BOOL followingSegmentDotVisible = NO;
-    if (base::FeatureList::IsEnabled(kEnableCheckForNewFollowContent) &&
-        IsWebChannelsEnabled()) {
+    if (IsDotEnabledForNewFollowedContent() && IsWebChannelsEnabled()) {
       // Only show the dot if the user follows available publishers.
       followingSegmentDotVisible =
           [self doesFollowingFeedHaveContent] &&

ios/chrome/browser/ui/ntp/new_tab_page_feature.h

@@ -45,6 +45,10 @@ BASE_DECLARE_FEATURE(kEnableCheckVisibilityOnAttentionLogStart);
 // very short attention log.
 BASE_DECLARE_FEATURE(kEnableRefineDataSourceReloadReporting);
 
+// Flag to modify the feed header through the server. Enabling this feature on
+// its own does nothing; relies on feature parameters.
+BASE_DECLARE_FEATURE(kFeedHeaderSettings);
+
 // Flag to override feed settings through the server. Enabling this feature on
 // its own does nothing; relies on feature parameters.
 BASE_DECLARE_FEATURE(kOverrideFeedSettings);
@@ -126,4 +130,15 @@ bool IsCheckVisibilityOnAttentionLogStartEnabled();
 // attention log.
 bool IsRefineDataSourceReloadReportingEnabled();
 
+// YES if the Following feed header should not be sticky.
+bool IsStickyHeaderDisabledForFollowingFeed();
+
+// YES if a dot should appear to indicate that there is new content in the
+// Following feed.
+bool IsDotEnabledForNewFollowedContent();
+
+// Returns a custom height for the Following feed header if it is overridden
+// from the server, or returns the default value.
+int FollowingFeedHeaderHeight();
+
 #endif  // IOS_CHROME_BROWSER_UI_NTP_NEW_TAB_PAGE_FEATURE_H_

ios/chrome/browser/ui/ntp/new_tab_page_feature.mm

@@ -55,8 +55,10 @@
              "EnableRefineDataSourceReloadReporting",
              base::FEATURE_DISABLED_BY_DEFAULT);
 
-// Flag to override feed settings through the server. Enabling this feature on
-// its own does nothing; relies on feature parameters.
+BASE_FEATURE(kFeedHeaderSettings,
+             "FeedHeaderSettings",
+             base::FEATURE_DISABLED_BY_DEFAULT);
+
 BASE_FEATURE(kOverrideFeedSettings,
              "OverrideFeedSettings",
              base::FEATURE_DISABLED_BY_DEFAULT);
@@ -80,6 +82,13 @@
 const char kFollowingFeedDefaultSortTypeGroupedByPublisher[] =
     "GroupedByPublisher";
 
+// Feature parameters for `kFeedHeaderSettings`.
+const char kEnableDotForNewFollowedContent[] =
+    "kEnableDotForNewFollowedContent";
+const char kDisableStickyHeaderForFollowingFeed[] =
+    "DisableStickyHeaderForFollowingFeed";
+const char kOverrideFeedHeaderHeight[] = "OverrideFeedHeaderHeight";
+
 // Feature parameters for `kOverrideFeedSettings`.
 const char kFeedSettingRefreshThresholdInSeconds[] =
     "RefreshThresholdInSeconds";
@@ -147,3 +156,20 @@ bool IsCheckVisibilityOnAttentionLogStartEnabled() {
 bool IsRefineDataSourceReloadReportingEnabled() {
   return base::FeatureList::IsEnabled(kEnableRefineDataSourceReloadReporting);
 }
+
+bool IsStickyHeaderDisabledForFollowingFeed() {
+  return base::GetFieldTrialParamByFeatureAsBool(
+      kFeedHeaderSettings, kDisableStickyHeaderForFollowingFeed, false);
+}
+
+bool IsDotEnabledForNewFollowedContent() {
+  return base::GetFieldTrialParamByFeatureAsBool(
+      kFeedHeaderSettings, kEnableDotForNewFollowedContent, false);
+}
+
+int FollowingFeedHeaderHeight() {
+  int defaultWebChannelsHeaderHeight = 52;
+  return base::GetFieldTrialParamByFeatureAsInt(kFeedHeaderSettings,
+                                                kOverrideFeedHeaderHeight,
+                                                defaultWebChannelsHeaderHeight);
+}