Refactor FXIOS-14049 #30453 ⁃ Enable Native error pages by default for develop (#30456)

* Enable error pages by default + small refactor

* Remove code that handle other error pages cases causing limbo state

Author: yoanarios

firefox-ios/Client/Frontend/Browser/BrowserViewController/Extensions/BrowserViewController+WebViewDelegates.swift

@@ -1031,8 +1031,8 @@ extension BrowserViewController: WKNavigationDelegate {
                     CFNetworkErrors.cfurlErrorNotConnectedToInternet.rawValue
                 )
 
-                if isNativeErrorPageEnabled {
-                    guard isNICErrorPageEnabled && error.code == noInternetErrorCode else { return }
+                // Only handle No internet access because other cases show about:blank page
+                if isNICErrorPageEnabled && error.code == noInternetErrorCode {
                     let action = NativeErrorPageAction(networkError: error,
                                                        windowUUID: windowUUID,
                                                        actionType: NativeErrorPageActionType.receivedError

firefox-ios/Client/Frontend/Browser/BrowserViewController/Views/BrowserViewController.swift

@@ -1943,11 +1943,10 @@ class BrowserViewController: UIViewController,
         let isNICErrorCode = url.absoluteString.contains(String(Int(
             CFNetworkErrors.cfurlErrorNotConnectedToInternet.rawValue)))
         let noInternetConnectionEnabled = isNICErrorCode && isNICErrorPageEnabled
-        let genericErrorPageEnabled = isErrorURL && isNativeErrorPageEnabled
 
         if isAboutHomeURL {
             showEmbeddedHomepage(inline: true, isPrivate: tabManager.selectedTab?.isPrivate ?? false)
-        } else if genericErrorPageEnabled && noInternetConnectionEnabled {
+        } else if isErrorURL && noInternetConnectionEnabled {
             showEmbeddedNativeErrorPage()
         } else {
             showEmbeddedWebview()

firefox-ios/Client/Frontend/InternalSchemeHandler/ErrorPageHelper.swift

@@ -175,9 +175,8 @@ class ErrorPageHandler: InternalSchemeResponse, FeatureFlaggable {
             CFNetworkErrors.cfurlErrorNotConnectedToInternet.rawValue
         )
 
-        if isNativeErrorPageEnabled && !useOldErrorPage {
-            return responseForNativeErrorPage(request: request)
-        } else if isNICErrorPageEnabled && (errCode == noInternetErrorCode) && !useOldErrorPage {
+        // Only handle No internet access because other cases show about:blank page
+        if isNICErrorPageEnabled && (errCode == noInternetErrorCode) && !useOldErrorPage {
             return responseForNativeErrorPage(request: request)
         } else {
             return responseForErrorWebPage(request: request)

firefox-ios/Client/Frontend/NativeErrorPage/NativeErrorPageFeatureFlag.swift

@@ -11,6 +11,7 @@ struct NativeErrorPageFeatureFlag: FeatureFlaggable {
 
     /// Temporary flag for showing no internet connection native error page only.
     var isNICErrorPageEnabled: Bool {
-        return featureFlags.isFeatureEnabled(.noInternetConnectionErrorPage, checking: .buildOnly)
+        return featureFlags.isFeatureEnabled(.nativeErrorPage, checking: .buildOnly) &&
+            featureFlags.isFeatureEnabled(.noInternetConnectionErrorPage, checking: .buildOnly)
     }
 }

firefox-ios/nimbus-features/nativeErrorPageFeature.yaml

@@ -22,5 +22,5 @@ features:
           no_internet_connection_error: false
       - channel: developer
         value:
-          enabled: false
-          no_internet_connection_error: false
+          enabled: true
+          no_internet_connection_error: true