[ios] Add a new experimental flag for refactoring of the TabStrip.

This CL adds the new flag for the refactoring of the the TabStrip.

Bug: 1128251, 1128249.
Change-Id: I13a5b6fef21ef5bc414848fcb3ab4bbc3099c5e5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2410068
Commit-Queue: Nazerke Kalidolda <nazerke@google.com>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#808840}

chrome/browser/flag-metadata.json

@@ -3125,6 +3125,11 @@
     "owners": [ "bsazonov", "aliceywang", "msarda", "fernandex" ],
     "expiry_milestone": 90
   },
+  {
+    "name": "modern-tab-strip",
+    "owners": [ "nazerke", "bling-flags" ],
+    "expiry_milestone": 92
+  },
   {
     "name": "mouse-subframe-no-implicit-capture",
     "owners": [ "eirage", "nzolghadr", "input-dev" ],

ios/chrome/browser/flags/about_flags.mm

@@ -693,6 +693,9 @@ const flags_ui::FeatureEntry kFeatureEntries[] = {
     {"default-browser-setting", flag_descriptions::kDefaultBrowserSettingsName,
      flag_descriptions::kDefaultBrowserSettingsDescription, flags_ui::kOsIos,
      FEATURE_VALUE_TYPE(kDefaultBrowserSettings)},
+    {"modern-tab-strip", flag_descriptions::kModernTabStripName,
+     flag_descriptions::kModernTabStripDescription, flags_ui::kOsIos,
+     FEATURE_VALUE_TYPE(kModernTabStrip)},
 };
 
 bool SkipConditionalFeatureEntry(const flags_ui::FeatureEntry& entry) {

ios/chrome/browser/flags/ios_chrome_flag_descriptions.cc

@@ -365,6 +365,10 @@ const char kMobileIdentityConsistencyName[] = "Mobile identity consistency";
 const char kMobileIdentityConsistencyDescription[] =
     "Enables identity consistency on mobile by decoupling sync and sign-in.";
 
+const char kModernTabStripName[] = "Modern TabStrip";
+const char kModernTabStripDescription[] =
+    "When enabled, the newly implemented tabstrip can be tested.";
+
 const char kOmniboxPreserveDefaultMatchAgainstAsyncUpdateName[] =
     "Omnibox Preserve Default Match Against Async Update";
 const char kOmniboxPreserveDefaultMatchAgainstAsyncUpdateDescription[] =

ios/chrome/browser/flags/ios_chrome_flag_descriptions.h

@@ -317,6 +317,13 @@ extern const char kMobileGoogleSRPDescription[];
 extern const char kMobileIdentityConsistencyName[];
 extern const char kMobileIdentityConsistencyDescription[];
 
+// TODO(crbug.com/1128242): Remove this flag after the refactoring work is
+// finished.
+// Title and description for the flag used to test the newly
+// implemented tabstrip.
+extern const char kModernTabStripName[];
+extern const char kModernTabStripDescription[];
+
 // Title and description for the flag to preserve the default match when an
 // async match updates.
 extern const char kOmniboxPreserveDefaultMatchAgainstAsyncUpdateName[];

ios/chrome/browser/ui/ui_feature_flags.cc

@@ -68,3 +68,8 @@ const base::Feature kDefaultBrowserFullscreenPromo{
 
 const base::Feature kDefaultBrowserSettings{"DefaultBrowserSettings",
                                             base::FEATURE_ENABLED_BY_DEFAULT};
+
+// TODO(crbug.com/1128242): Remove this flag after the refactoring work is
+// finished.
+const base::Feature kModernTabStrip{"ModernTabStrip",
+                                    base::FEATURE_DISABLED_BY_DEFAULT};

ios/chrome/browser/ui/ui_feature_flags.h

@@ -77,4 +77,8 @@ extern const base::Feature kDefaultBrowserFullscreenPromo;
 // Settings.app to update the default browser.
 extern const base::Feature kDefaultBrowserSettings;
 
+// TODO(crbug.com/1128242): Remove this flag after the refactoring work is
+// finished. Flag to modernize the tabstrip without disturbing the existing one.
+extern const base::Feature kModernTabStrip;
+
 #endif  // IOS_CHROME_BROWSER_UI_UI_FEATURE_FLAGS_H_