Bugfix FXIOS-9906 - Send ok response to can_link_account channel message

firefox-ios/RustFxA/FxAWebViewModel.swift

@@ -22,7 +22,7 @@ enum FxAPageType: Equatable {
 // See https://mozilla.github.io/ecosystem-platform/docs/fxa-engineering/fxa-webchannel-protocol
 // For details on message types.
 private enum RemoteCommand: String {
-    // case canLinkAccount = "can_link_account"
+     case canLinkAccount = "fxaccounts:can_link_account"
     // case loaded = "fxaccounts:loaded"
     case status = "fxaccounts:fxa_status"
     case oauthLogin = "fxaccounts:oauth_login"
@@ -283,6 +283,10 @@ extension FxAWebViewModel {
                                         email: email,
                                         verified: verified)
                 profile.rustFxA.accountManager?.setUserData(userData: userData) { }
+            case .canLinkAccount:
+                if let id = id {
+                    onCanLinkAccount(msgId: id, webView: webView)
+                }
             }
         }
     }
@@ -393,6 +397,19 @@ extension FxAWebViewModel {
         }
     }
 
+    private func onCanLinkAccount(msgId: Int, webView: WKWebView) {
+        let cmd = RemoteCommand.canLinkAccount.rawValue
+        let typeId = "account_updates"
+        // Respond with an 'ok' message immediately today so FxA does not need to support conditional logic on the
+        // server-side just for iOS.
+        // For proper account merging support, see: https://github.com/mozilla-mobile/firefox-ios/issues/21873
+        let data = """
+            { "ok": true }
+        """
+
+        runJS(webView: webView, typeId: typeId, messageId: msgId, command: cmd, data: data)
+    }
+
     func shouldAllowRedirectAfterLogIn(basedOn navigationURL: URL?) -> WKNavigationActionPolicy {
         // Cancel navigation that happens after login to an account, which is when a redirect to `redirectURL` happens.
         // The app handles this event fully in native UI.