Disable test on iPad when slim navigation is enabled

Bug: 968296
Change-Id: I893b369b466545e83a91a530e3b44be967934734
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1644010
Auto-Submit: Mike Dougherty <michaeldo@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Commit-Queue: Mike Dougherty <michaeldo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#666051}

ios/chrome/browser/web/forms_egtest.mm

@@ -280,6 +280,11 @@ id<GREYMatcher> ResendPostButtonMatcher() {
 // Tests that a POST followed by tapping back to the form page and then tapping
 // forward to the result page resends data.
 - (void)testRepostFormAfterTappingBackAndForward {
+  // TODO(crbug.com/968296): Test is failing on iPad for slim nav.
+  if (IsIPadIdiom() && web::GetWebClient()->IsSlimNavigationManagerEnabled()) {
+    EARL_GREY_TEST_DISABLED(@"Test disabled on iPad.");
+  }
+
   [self setUpFormTestSimpleHttpServer];
   const GURL destinationURL = GetDestinationUrl();