generation: ensure password gen feature flag is respected (#583)

This was originally introduced as a commit squashed into 8b046b1
(Android: enable iframe support (#536), 2024-04-09), but was accidentally
removed via 18dd599 (android: revert "Android: enable iframe support
(#536)" (#582), 2024-06-20). Reintroduce that commit, to ensure the
`password_generation` runtime config flag is again respected and prevent
password prompts after a user clicks "Never save for site".

(cherry picked from commit 4c16e52)

src/Settings.js

@@ -198,11 +198,18 @@ export class Settings {
      * @param {{
      *   mainType: SupportedMainTypes
      *   subtype: import('./Form/matching.js').SupportedSubTypes | "unknown"
+     *   variant?: import('./Form/matching.js').SupportedVariants | ""
      * }} types
      * @returns {boolean}
      */
-    isTypeUnavailable ({mainType, subtype}) {
+    isTypeUnavailable ({mainType, subtype, variant}) {
         if (mainType === 'unknown') return true
+
+        // Ensure password generation feature flag is respected
+        if (subtype === 'password' && variant === 'new') {
+            return !this.featureToggles.password_generation
+        }
+
         if (!this.featureToggles[`inputType_${mainType}`] && subtype !== 'emailAddress') {
             return true
         }
@@ -223,11 +230,12 @@ export class Settings {
      * @param {{
      *   mainType: SupportedMainTypes
      *   subtype: import('./Form/matching.js').SupportedSubTypes | "unknown"
+     *   variant?: import('./Form/matching.js').SupportedVariants | ""
      * }} types
      * @returns {Promise<boolean>}
      */
-    async populateDataIfNeeded ({mainType, subtype}) {
-        if (this.isTypeUnavailable({mainType, subtype})) return false
+    async populateDataIfNeeded ({mainType, subtype, variant}) {
+        if (this.isTypeUnavailable({mainType, subtype, variant})) return false
         if (this.availableInputTypes?.[mainType] === undefined) {
             await this.populateData()
             return true
@@ -247,7 +255,7 @@ export class Settings {
      * @returns {boolean}
      */
     canAutofillType ({mainType, subtype, variant}, inContextSignup) {
-        if (this.isTypeUnavailable({ mainType, subtype })) return false
+        if (this.isTypeUnavailable({ mainType, subtype, variant })) return false
 
         // If it's an email field and Email Protection is enabled, return true regardless of other options
         const isEmailProtectionEnabled = this.featureToggles.emailProtection && this.availableInputTypes.email

src/Settings.test.js

@@ -50,6 +50,17 @@ describe('Settings', () => {
                     expect(settings.canAutofillType({ mainType: 'credentials', subtype: 'password', variant: 'current' }, null)).toBe(false)
                 }
             ],
+            [
+                { password_generation: false },
+                {
+                    ...createAvailableInputTypes({
+                        credentials: {username: true, password: true}
+                    })
+                },
+                (settings) => {
+                    expect(settings.canAutofillType({ mainType: 'credentials', subtype: 'password', variant: 'new' }, null)).toBe(false)
+                }
+            ],
             [
                 {},
                 {