Hide SetDisplayingNativeError behind kWebErrorPages flag.

SetDisplayingNativeError should not be used if kWebErrorPages is
enabled.

Bug: 725241
Cq-Include-Trybots: luci.chromium.try:ios-simulator-cronet;luci.chromium.try:ios-simulator-full-configs
Change-Id: I8a8be55dc0312fe60e9a4d403ed5e1ad78cbbf32
Reviewed-on: https://chromium-review.googlesource.com/c/1288975Reviewed-by: Danyao Wang <danyao@chromium.org>
Commit-Queue: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#600896}

ios/web/navigation/error_retry_state_machine.h

@@ -84,6 +84,9 @@ class ErrorRetryStateMachine {
   // Transitions the state machine to kDisplayingNativeErrorForFailedNavigation.
   void SetDisplayingNativeError();
 
+  // Transitions the state machine to kDisplayingWebErrorForFailedNavigation.
+  void SetDisplayingWebError();
+
   // Runs state transitions upon a failed provisional navigation.
   ErrorRetryCommand DidFailProvisionalNavigation(const GURL& web_view_url,
                                                  const GURL& error_url);

ios/web/navigation/error_retry_state_machine.mm

@@ -45,6 +45,23 @@ void ErrorRetryStateMachine::SetDisplayingNativeError() {
   state_ = ErrorRetryState::kDisplayingNativeErrorForFailedNavigation;
 }
 
+void ErrorRetryStateMachine::SetDisplayingWebError() {
+  // Web error is displayed in two scenarios:
+  // (1) Placeholder entry for network load error finished loading in web view.
+  //     This is the common case.
+  // (2) Retry of a previously failed load failed in SSL error. This can happen
+  //     when the first navigation failed in offline mode. SSL interstitial does
+  //     not normally trigger ErrorRetryStateMachine because the error page is
+  //     not to become part of the navigation history. This leaves the item
+  //     stuck in the transient kRetryFailedNavigationItem state. So for this
+  //     specific case, treat the SSL interstitial as a web error so that
+  //     error retry works as expected on subsequent back/forward navigations.
+  DCHECK(state_ == ErrorRetryState::kReadyToDisplayErrorForFailedNavigation ||
+         state_ == ErrorRetryState::kRetryFailedNavigationItem)
+      << "Unexpected error retry state: " << static_cast<int>(state_);
+  state_ = ErrorRetryState::kDisplayingWebErrorForFailedNavigation;
+}
+
 ErrorRetryCommand ErrorRetryStateMachine::DidFailProvisionalNavigation(
     const GURL& web_view_url,
     const GURL& error_url) {

ios/web/navigation/error_retry_state_machine_unittest.mm

@@ -4,7 +4,9 @@
 
 #include "ios/web/navigation/error_retry_state_machine.h"
 
+#include "base/feature_list.h"
 #include "ios/web/navigation/wk_navigation_util.h"
+#include "ios/web/public/features.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #import "testing/gtest_mac.h"
 #include "testing/platform_test.h"
@@ -41,10 +43,16 @@ TEST_F(ErrorRetryStateMachineTest, OfflineThenReload) {
   ASSERT_EQ(ErrorRetryState::kReadyToDisplayErrorForFailedNavigation,
             machine.state());
 
-  // Presents error in native view.
-  machine.SetDisplayingNativeError();
-  ASSERT_EQ(ErrorRetryState::kDisplayingNativeErrorForFailedNavigation,
-            machine.state());
+  // Presents error.
+  if (base::FeatureList::IsEnabled(web::features::kWebErrorPages)) {
+    machine.SetDisplayingWebError();
+    ASSERT_EQ(ErrorRetryState::kDisplayingWebErrorForFailedNavigation,
+              machine.state());
+  } else {
+    machine.SetDisplayingNativeError();
+    ASSERT_EQ(ErrorRetryState::kDisplayingNativeErrorForFailedNavigation,
+              machine.state());
+  }
 
   // Reload the failed navigation.
   ASSERT_EQ(ErrorRetryCommand::kRewriteWebViewURL,

ios/web/web_state/ui/crw_web_controller.mm

@@ -3893,7 +3893,11 @@ registerLoadRequestForURL:(const GURL&)requestURL
         self.navigationManagerImpl, context->GetNavigationItemUniqueID());
     if (item && item->error_retry_state_machine().state() ==
                     web::ErrorRetryState::kRetryFailedNavigationItem) {
-      item->error_retry_state_machine().SetDisplayingNativeError();
+      if (base::FeatureList::IsEnabled(web::features::kWebErrorPages)) {
+        item->error_retry_state_machine().SetDisplayingWebError();
+      } else {
+        item->error_retry_state_machine().SetDisplayingNativeError();
+      }
     }
   }