Fix flaky NewTabPageTestCase.testOmnibox

ios/chrome/browser/ui/ntp/new_tab_page_egtest.mm

Index: ios/chrome/browser/ui/ntp/new_tab_page_egtest.mm
diff --git a/ios/chrome/browser/ui/ntp/new_tab_page_egtest.mm b/ios/chrome/browser/ui/ntp/new_tab_page_egtest.mm
index 3fd2754d90e2f3c5a113564865035cd2e50fcda2..384447094e146cbcde58d9b24882ba84364863fe 100644
--- a/ios/chrome/browser/ui/ntp/new_tab_page_egtest.mm
+++ b/ios/chrome/browser/ui/ntp/new_tab_page_egtest.mm
@@ -28,6 +28,7 @@
 
 @interface GoogleLandingController (ExposedForTesting)
 - (BOOL)scrolledToTop;
+- (BOOL)animateHeader;
 @end
 
 namespace {
@@ -86,6 +87,11 @@ void AssertNTPScrolledToTop(bool scrolledToTop) {
       chrome_test_util::GetCurrentNewTabPageController();
   GoogleLandingController* google_landing_controller =
       [ntp_controller googleLandingController];
+  [[GREYCondition
+      conditionWithName:@"Wait for end of animation."
+                  block:^BOOL {
+                    return ![google_landing_controller animateHeader];
+                  }] waitWithTimeout:testing::kWaitForUIElementTimeout];
   GREYAssertTrue([google_landing_controller scrolledToTop] == scrolledToTop,
                  @"scrolledToTop_ does not match expected value");
 }