Add js user agent client hints brand header-matching feature (#4224)

* Add ua-ch-brands feature

* Lint

* Add schema

* Zap extraneous comments

* Liiint

* Gate to internal & preview channels

* Merge conditions into 1

* Fix angry test

* Experiment w/ swtiching syntax

* Annnnd that was not the problem it seems

Author: laghee

features/ua-ch-brands.json

@@ -0,0 +1,7 @@
+{
+    "_meta": {
+        "description": "User agent client hint brands for the browser JavaScript API."
+    },
+    "state": "disabled",
+    "exceptions": []
+}

index.js

@@ -144,6 +144,7 @@ const featuresToIncludeTempUnprotectedExceptions = [
     'trackingCookies1p',
     'trackingCookies3p',
     'trackingParameters',
+    'uaChBrands',
     'unprotectedTemporary',
     'webCompat',
 ];

overrides/windows-override.json

@@ -2555,6 +2555,26 @@
         "clientBrandHint": {
             "state": "enabled"
         },
+        "uaChBrands": {
+            "state": "enabled",
+            "settings": {
+                "additionalCheck": "disabled",
+                "conditionalChanges": [
+                    {
+                        "condition": [
+                            { "internal": true },
+                            { "preview": true }],
+                        "patchSettings": [
+                            {
+                                "op": "replace",
+                                "path": "/additionalCheck",
+                                "value": "enabled"
+                            }
+                        ]
+                    }
+                ]
+            }
+        },
         "privacyPro": {
             "state": "enabled",
             "features": {

schema/config.ts

@@ -24,6 +24,7 @@ import { Taskbar } from './features/taskbar';
 import { AppHealth } from './features/appHealth';
 import { ElementHidingFeature } from './features/element-hiding';
 import { RequestBlocklistFeature } from './features/request-blocklist';
+import { UaChBrandsFeature } from './features/ua-ch-brands';
 import { UrlPredictorFeature } from './features/url-predictor';
 
 export { WebCompatSettings } from './features/webcompat';
@@ -73,6 +74,7 @@ export type ConfigV5<VersionType> = {
         customUserAgent?: CustomUserAgentFeature<VersionType>;
         elementHiding?: ElementHidingFeature<VersionType>;
         requestBlocklist?: RequestBlocklistFeature<VersionType>;
+        uaChBrands?: UaChBrandsFeature<VersionType>;
         urlPredictor?: UrlPredictorFeature<VersionType>;
     };
     unprotectedTemporary: SiteException[];

schema/feature.ts

@@ -65,6 +65,7 @@ type ConditionBlock = {
     minSupportedVersion?: number;
     maxSupportedVersion?: number;
     internal?: boolean;
+    preview?: boolean;
     context?: {
         top?: boolean;
         frame?: boolean;

schema/features/ua-ch-brands.ts

@@ -0,0 +1,11 @@
+import { CSSInjectFeatureSettings, Feature, FeatureState } from '../feature';
+
+type StateToggle = 'enabled' | 'disabled';
+
+type UaChBrandsSettings = CSSInjectFeatureSettings<{
+    filterWebView2?: StateToggle;
+    overrideEdge?: StateToggle;
+    additionalCheck?: FeatureState;
+}>;
+
+export type UaChBrandsFeature<VersionType> = Feature<UaChBrandsSettings, VersionType>;