Feature Flag for Discover Feed in Bling NTP

Change-Id: I04d3b1315656d9adedd6871435ef0686924bb41a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2202387Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Commit-Queue: Adam Trudeau-Arcaro <adamta@google.com>
Cr-Commit-Position: refs/heads/master@{#770913}

chrome/browser/flag-metadata.json

@@ -952,6 +952,11 @@
     "owners": [ "alemate" ],
     "expiry_milestone": 80
   },
+  {
+    "name": "discover-feed-ntp-ios",
+    "owners": [ "adamta", "sczs" ],
+    "expiry_milestone": 89
+  },
   {
     "name": "display-change-modal",
     "owners": [ "baileyberro", "zentaro" ],

ios/chrome/browser/flags/BUILD.gn

@@ -47,6 +47,7 @@ source_set("flags") {
     "//ios/chrome/browser/passwords:feature_flags",
     "//ios/chrome/browser/policy:feature_flags",
     "//ios/chrome/browser/ui:feature_flags",
+    "//ios/chrome/browser/ui/content_suggestions:feature_flags",
     "//ios/chrome/browser/ui/download:features",
     "//ios/chrome/browser/ui/fullscreen:feature_flags",
     "//ios/chrome/browser/ui/infobars:feature_flags",

ios/chrome/browser/flags/about_flags.mm

@@ -59,6 +59,7 @@
 #include "ios/chrome/browser/passwords/password_manager_features.h"
 #include "ios/chrome/browser/policy/policy_features.h"
 #include "ios/chrome/browser/system_flags.h"
+#import "ios/chrome/browser/ui/content_suggestions/content_suggestions_feature.h"
 #import "ios/chrome/browser/ui/download/features.h"
 #import "ios/chrome/browser/ui/fullscreen/fullscreen_features.h"
 #import "ios/chrome/browser/ui/infobars/infobar_feature.h"
@@ -632,7 +633,9 @@ const flags_ui::FeatureEntry kFeatureEntries[] = {
     {"safety-check-ios", flag_descriptions::kSafetyCheckIOSName,
      flag_descriptions::kSafetyCheckIOSDescription, flags_ui::kOsIos,
      FEATURE_VALUE_TYPE(kSafetyCheckIOS)},
-
+    {"discover-feed-ntp-ios", flag_descriptions::kDiscoverFeedInNtpName,
+     flag_descriptions::kDiscoverFeedInNtpDescription, flags_ui::kOsIos,
+     FEATURE_VALUE_TYPE(kDiscoverFeedInNtp)},
 };
 
 bool SkipConditionalFeatureEntry(const flags_ui::FeatureEntry& entry) {

ios/chrome/browser/flags/ios_chrome_flag_descriptions.cc

@@ -178,6 +178,10 @@ const char kDisableAnimationOnLowBatteryName[] =
 const char kDisableAnimationOnLowBatteryDescription[] =
     "Disable animations when battery level goes below 20%";
 
+const char kDiscoverFeedInNtpName[] = "Enable Discover feed in new tab page";
+const char kDiscoverFeedInNtpDescription[] =
+    "When enabled, replaces articles feed with Discover feed in new tab page.";
+
 const char kDownloadInfobarMessagesUIName[] = "Download Infobars Messages UI";
 const char kDownloadInfobarMessagesUIDescription[] =
     "When enabled Downloads use the new Messages UI.";

ios/chrome/browser/flags/ios_chrome_flag_descriptions.h

@@ -148,6 +148,11 @@ extern const char kDetectMainThreadFreezeDescription[];
 extern const char kDisableAnimationOnLowBatteryName[];
 extern const char kDisableAnimationOnLowBatteryDescription[];
 
+// Title and description for the flag to replace the Zine feed with the
+// Discover feed in the Bling NTP.
+extern const char kDiscoverFeedInNtpName[];
+extern const char kDiscoverFeedInNtpDescription[];
+
 // Title and description for the flag to enable the Messages UI for downloads.
 extern const char kDownloadInfobarMessagesUIName[];
 extern const char kDownloadInfobarMessagesUIDescription[];

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

@@ -419,3 +419,12 @@ source_set("test_support") {
   ]
   configs += [ "//build/config/compiler:enable_arc" ]
 }
+
+source_set("feature_flags") {
+  configs += [ "//build/config/compiler:enable_arc" ]
+  sources = [
+    "content_suggestions_feature.h",
+    "content_suggestions_feature.mm",
+  ]
+  public_deps = [ "//base" ]
+}

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

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_CONTENT_SUGGESTIONS_FEATURE_H_
+#define IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_CONTENT_SUGGESTIONS_FEATURE_H_
+
+#include "base/feature_list.h"
+
+// Feature to choose between the old Zine feed or the new Discover feed in the
+// Bling new tab page.
+// Use IsDiscoverFeedEnabled() instead of this constant directly.
+extern const base::Feature kDiscoverFeedInNtp;
+
+// Whether the Discover feed is enabled instead of the Zine feed.
+bool IsDiscoverFeedEnabled();
+
+#endif  // IOS_CHROME_BROWSER_UI_CONTENT_SUGGESTIONS_CONTENT_SUGGESTIONS_FEATURE_H_

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

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import "ios/chrome/browser/ui/content_suggestions/content_suggestions_feature.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+// Feature disabled by default to keep showing old Zine feed.
+const base::Feature kDiscoverFeedInNtp{"DiscoverFeedInNtp",
+                                       base::FEATURE_DISABLED_BY_DEFAULT};
+
+bool IsDiscoverFeedEnabled() {
+  return base::FeatureList::IsEnabled(kDiscoverFeedInNtp);
+}