Enable testShowJavaScriptAfterNewTabAnimation for iPad

ios/chrome/browser/ui/dialogs/javascript_dialog_egtest.mm

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import <EarlGrey/EarlGrey.h>
 #import <UIKit/UIKit.h>
 #import <XCTest/XCTest.h>
 
 #import "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 295 matching lines @@
 
   // Dismiss JavaScript alert by tapping Cancel.
   [[EarlGrey selectElementWithMatcher:chrome_test_util::CancelButton()]
       performAction:grey_tap()
               error:&errorCancel];
   // Dismiss JavaScript alert by tapping OK.
   id<GREYMatcher> OKButton =
       chrome_test_util::ButtonWithAccessibilityLabelId(IDS_OK);
   [[EarlGrey selectElementWithMatcher:OKButton] performAction:grey_tap()
                                                         error:&errorOK];
+  // Reenable synchronization in case it was disabled by a test.  See comments
+  // in testShowJavaScriptAfterNewTabAnimation for details.
+  [[GREYConfiguration sharedInstance]
+          setValue:@(YES)
+      forConfigKey:kGREYConfigKeySynchronizationEnabled];
 
   if (!errorOK || !errorCancel) {
     GREYFail(@"There are still alerts");
   }
   [super tearDown];
 }
 
 #pragma mark - Utility
 
 - (void)loadBlankTestPage {
@@ skipping 222 matching lines @@
 
 // Tests that an alert is presented after a new tab animation is finished.
 - (void)testShowJavaScriptAfterNewTabAnimation {
 // TODO(crbug.com/663026): Reenable the test for devices.
 #if !TARGET_IPHONE_SIMULATOR
   EARL_GREY_TEST_DISABLED(@"Disabled for devices because existing system "
                           @"alerts would prevent app alerts to present "
                           @"correctly.");
 #endif
 
-  // TODO(crbug.com/711291): reenable this on tablets.
-  if (IsIPadIdiom()) {
-    EARL_GREY_TEST_DISABLED(@"Disabled for iPad.");
-  }
-
   // Load the test page with a link to kOnLoadAlertURL and long tap on the link.
   [self loadPageWithLink];
   id<GREYMatcher> webViewMatcher =
       chrome_test_util::WebViewContainingText(std::string(kPageWithLinkText));
   [[EarlGrey selectElementWithMatcher:webViewMatcher]
       performAction:chrome_test_util::LongPressElementForContextMenu(
                         kLinkID, true /* menu should appear */)];
 
   // Tap on the "Open In New Tab" button.
   id<GREYMatcher> newTabMatcher = testing::ContextMenuItemWithText(
       l10n_util::GetNSStringWithFixup(IDS_IOS_CONTENT_CONTEXT_OPENLINKNEWTAB));
   [[EarlGrey selectElementWithMatcher:newTabMatcher] performAction:grey_tap()];
 
+  // This test case requires that a dialog is presented in the onload event so
+  // that the DialogPresenter attempts to display during a new tab animation.
+  // Because presenting a dialog halts the JavaScript execution on the page,
+  // this prevents the page loaded event from being received until the alert is
+  // closed.  On iPad, this means that there is a loading indicator that
+  // continues to animate until the dialog is closed.  Disabling EarlGrey
+  // synchronization code for iPad allows the test to detect and dismiss the
+  // dialog while this animation is occurring.
+  if (IsIPadIdiom()) {
+    [[GREYConfiguration sharedInstance]
+            setValue:@(NO)
+        forConfigKey:kGREYConfigKeySynchronizationEnabled];
+  }
+
   // Wait for the alert to be shown.
   NSString* alertLabel = [DialogPresenter
       localizedTitleForJavaScriptAlertFromPage:HttpServer::MakeUrl(
                                                    kJavaScriptTestURL)];
   WaitForAlertToBeShown(alertLabel);
 
   // Verify that the omnibox shows the correct URL when the dialog is visible.
   GURL onloadURL = HttpServer::MakeUrl(kOnLoadAlertURL);
   std::string title = base::UTF16ToUTF8(web::GetDisplayTitleForUrl(onloadURL));
   [[EarlGrey selectElementWithMatcher:chrome_test_util::OmniboxText(title)]
       assertWithMatcher:grey_notNil()];
 
   // Close the alert.
   TapOK();
+
+  // Reenable synchronization on iPads now that the dialog has been dismissed.
+  if (IsIPadIdiom()) {
+    [[GREYConfiguration sharedInstance]
+            setValue:@(YES)
+        forConfigKey:kGREYConfigKeySynchronizationEnabled];
+  }
 }
 
 @end