Add Feature flag for new Chrome Empties UI

This flag will be used to show or hide the new UI in Chrome empty states.

Bug: 1086688
Change-Id: I885d642f1f2e87f9b3b3346f3c1c7f8f80f064dd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2216547
Commit-Queue: Maxime Charland <mcharland@google.com>
Reviewed-by: Tommy Martino <tmartino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#773786}

chrome/browser/flag-metadata.json

@@ -2766,6 +2766,11 @@
     // testing and should not be removed.
     "expiry_milestone": -1
   },
+  {
+    "name": "illustrated-empty-states",
+    "owners": [ "mcharland", "tmartino" ],
+    "expiry_milestone": 88
+  },
   {
     "name": "improved-cookie-controls",
     "owners": [ "dullweber", "huanzhong" ],

ios/chrome/browser/flags/about_flags.mm

@@ -642,6 +642,9 @@ const flags_ui::FeatureEntry kFeatureEntries[] = {
      flags_ui::kOsIos,
      FEATURE_VALUE_TYPE(
          autofill::features::kAutofillEnableCardNicknameUpstream)},
+    {"illustrated-empty-states", flag_descriptions::kIllustratedEmptyStatesName,
+     flag_descriptions::kIllustratedEmptyStatesDescription, flags_ui::kOsIos,
+     FEATURE_VALUE_TYPE(kIllustratedEmptyStates)},
 };
 
 bool SkipConditionalFeatureEntry(const flags_ui::FeatureEntry& entry) {

ios/chrome/browser/flags/ios_chrome_flag_descriptions.cc

@@ -257,6 +257,10 @@ const char kFullscreenControllerBrowserScopedDescription[] =
     "When enabled, FullscreenController will be stored and retrieved using the "
     "Browser.";
 
+const char kIllustratedEmptyStatesName[] = "Illustrated empty states";
+const char kIllustratedEmptyStatesDescription[] =
+    "Display new illustrations and layout on empty states.";
+
 const char kInfobarOverlayUIName[] = "Use OverlayPresenter for infobars";
 const char kInfobarOverlayUIDescription[] =
     "When enabled alongside the Infobar UI Reboot, infobars will be presented "

ios/chrome/browser/flags/ios_chrome_flag_descriptions.h

@@ -222,6 +222,11 @@ extern const char kFullscreenSmoothScrollingDescription[];
 extern const char kFullscreenControllerBrowserScopedName[];
 extern const char kFullscreenControllerBrowserScopedDescription[];
 
+// Title and description for the flag to enable new illustrations and
+// UI on empty states.
+extern const char kIllustratedEmptyStatesName[];
+extern const char kIllustratedEmptyStatesDescription[];
+
 // Title and description for the flag to present the new UI Reboot on Infobars
 // using OverlayPresenter.
 extern const char kInfobarOverlayUIName[];

ios/chrome/browser/ui/ui_feature_flags.cc

@@ -56,3 +56,6 @@ const base::Feature kEnableIOSManagedSettingsUI{
 
 const base::Feature kSafetyCheckIOS{"SafetyCheckIOS",
                                     base::FEATURE_DISABLED_BY_DEFAULT};
+
+const base::Feature kIllustratedEmptyStates{"IllustratedEmptyStates",
+                                            base::FEATURE_DISABLED_BY_DEFAULT};

ios/chrome/browser/ui/ui_feature_flags.h

@@ -63,4 +63,7 @@ extern const base::Feature kEnableIOSManagedSettingsUI;
 // Enables the safety check in settings on iOS.
 extern const base::Feature kSafetyCheckIOS;
 
+// Feature flag to enable new illustrations and UI on empty states.
+extern const base::Feature kIllustratedEmptyStates;
+
 #endif  // IOS_CHROME_BROWSER_UI_UI_FEATURE_FLAGS_H_