[iOS] Don't load new error navigation while restoring

This CL makes sure that when the application doesn't start a new
navigation when an error occurs while loading a session restoration
page.

Fixed: 1138895
Change-Id: I9d0b4558ddccf3f53f9dd8dd7d671434b31f1d77
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2520896
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#825404}

ios/chrome/browser/web/BUILD.gn

@@ -451,6 +451,7 @@ source_set("eg2_tests") {
     "//ios/chrome/browser:chrome_url_constants",
     "//ios/chrome/browser/ui/infobars/banners:public",
     "//ios/chrome/browser/ui/popup_menu:constants",
+    "//ios/chrome/browser/ui/tab_grid:features",
     "//ios/chrome/test:eg_test_support+eg2",
     "//ios/chrome/test/earl_grey:eg_test_support+eg2",
     "//ios/net:test_support",

ios/chrome/browser/web/error_page_egtest.mm

@@ -6,10 +6,12 @@
 #include <string>
 
 #include "base/bind.h"
+#import "ios/chrome/browser/ui/tab_grid/features.h"
 #import "ios/chrome/test/earl_grey/chrome_earl_grey.h"
 #import "ios/chrome/test/earl_grey/chrome_test_case.h"
 #import "ios/testing/earl_grey/earl_grey_test.h"
 #include "ios/testing/embedded_test_server_handlers.h"
+#include "ios/web/common/features.h"
 #include "net/test/embedded_test_server/default_handlers.h"
 #include "net/test/embedded_test_server/http_request.h"
 #include "net/test/embedded_test_server/http_response.h"
@@ -36,6 +38,21 @@ std::string GetErrorMessage() {
 @implementation ErrorPageTestCase
 @synthesize serverRespondsWithContent = _serverRespondsWithContent;
 
+- (AppLaunchConfiguration)appConfigurationForTestCase {
+  AppLaunchConfiguration config;
+
+  // Features are enabled or disabled based on the name of the test that is
+  // running. This is done because it is inefficient to use
+  // ensureAppLaunchedWithConfiguration for each test.
+  if ([self isRunningTest:@selector(testRestoreErrorPage)]) {
+    config.features_disabled.push_back(kEnableCloseAllTabsConfirmation);
+    config.features_enabled.push_back(web::features::kUseJSForErrorPage);
+  } else {
+    config.features_enabled.push_back(kEnableCloseAllTabsConfirmation);
+  }
+  return config;
+}
+
 - (void)setUp {
   [super setUp];
 
@@ -74,4 +91,24 @@ std::string GetErrorMessage() {
   [ChromeEarlGrey waitForWebStateContainingText:GetErrorMessage()];
 }
 
+// Loads a URL then restore the session and fail during the reload
+- (void)testRestoreErrorPage {
+  // Load the page.
+  self.serverRespondsWithContent = YES;
+  [ChromeEarlGrey loadURL:self.testServer->GetURL("/echo-query?foo")];
+  [ChromeEarlGrey waitForWebStateContainingText:"foo"];
+  GREYAssertEqual(1, [ChromeEarlGrey navigationBackListItemsCount],
+                  @"The navigation back list should have only 1 entries before "
+                  @"the restoration.");
+
+  // Restore the session but with the page no longer loading.
+  self.serverRespondsWithContent = NO;
+  [ChromeEarlGrey triggerRestoreViaTabGridRemoveAllUndo];
+  [ChromeEarlGrey waitForWebStateContainingText:GetErrorMessage()];
+
+  GREYAssertEqual(1, [ChromeEarlGrey navigationBackListItemsCount],
+                  @"The navigation back list should still have only 1 entries "
+                  @"after the restoration.");
+}
+
 @end

ios/chrome/test/earl_grey/chrome_earl_grey.h

@@ -76,6 +76,9 @@ id ExecuteJavaScript(NSString* javascript, NSError* __autoreleasing* out_error);
 // induced on error.
 - (NSInteger)browsingHistoryEntryCount;
 
+// Gets the number of items in the back list.
+- (NSInteger)navigationBackListItemsCount;
+
 // Clears browsing cache. Raises an EarlGrey exception if history is not
 // cleared within a timeout.
 - (void)removeBrowsingCache;

ios/chrome/test/earl_grey/chrome_earl_grey.mm

@@ -133,6 +133,10 @@ GREY_STUB_CLASS_IN_APP_MAIN_QUEUE(ChromeEarlGreyAppInterface)
   return result;
 }
 
+- (NSInteger)navigationBackListItemsCount {
+  return [ChromeEarlGreyAppInterface navigationBackListItemsCount];
+}
+
 - (void)removeBrowsingCache {
   EG_TEST_HELPER_ASSERT_NO_ERROR(
       [ChromeEarlGreyAppInterface removeBrowsingCache]);

ios/chrome/test/earl_grey/chrome_earl_grey_app_interface.h

@@ -30,6 +30,9 @@
 + (NSInteger)browsingHistoryEntryCountWithError:
     (NSError* __autoreleasing*)error;
 
+// Gets the number of items in the back list. Returns -1 in case of error.
++ (NSInteger)navigationBackListItemsCount;
+
 // Clears browsing cache. Returns nil on success, or else an NSError indicating
 // the operation failed.
 + (NSError*)removeBrowsingCache;

ios/chrome/test/earl_grey/chrome_earl_grey_app_interface.mm

@@ -105,6 +105,15 @@ NSString* SerializedPref(const PrefService::Preference* pref) {
   return chrome_test_util::GetBrowsingHistoryEntryCount(error);
 }
 
++ (NSInteger)navigationBackListItemsCount {
+  web::WebState* webState = chrome_test_util::GetCurrentWebState();
+
+  if (!webState)
+    return -1;
+
+  return webState->GetNavigationManager()->GetBackwardItems().size();
+}
+
 + (NSError*)removeBrowsingCache {
   if (chrome_test_util::RemoveBrowsingCache()) {
     return nil;

ios/web/navigation/crw_wk_navigation_handler.mm

@@ -2049,14 +2049,16 @@ void ReportOutOfSyncURLInDidStartProvisionalNavigation(
   //   2. Current nav item has a failed URL. This may happen when
   //      back/forward/refresh on a loaded page;
   //   3. Current nav item is an irrelevant page.
-  // For 1&2, load an empty string to remove existing JS code.
+  //   4. Current nav item is a session restoration.
+  // For 1, 2 and 4, load an empty string to remove existing JS code.
   // For 3, load error page file to create a new nav item.
   // The actual error HTML will be loaded in didFinishNavigation callback.
   WKNavigation* errorNavigation = nil;
   if (provisionalLoad &&
       ![errorPage
           isErrorPageFileURLForFailedNavigationURL:backForwardItem.URL] &&
-      ![backForwardItem.URL isEqual:errorPage.failedNavigationURL]) {
+      ![backForwardItem.URL isEqual:errorPage.failedNavigationURL] &&
+      !web::wk_navigation_util::IsRestoreSessionUrl(backForwardItem.URL)) {
     errorNavigation = [webView loadFileURL:errorPage.errorPageFileURL
                    allowingReadAccessToURL:errorPage.errorPageFileURL];
   } else {