Disable EarlGrey web shell tests that fail on device.

ios/web/shell/test/page_state_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 <CoreGraphics/CoreGraphics.h>
 #import <EarlGrey/EarlGrey.h>
 #import <Foundation/Foundation.h>
 #import <XCTest/XCTest.h>
 
 #include "base/ios/ios_util.h"
@@ skipping 39 matching lines @@
 }  // namespace
 
 using web::test::HttpServer;
 
 // Page state test cases for the web shell.
 @interface PageStateTestCase : ShellBaseTestCase
 @end
 
 @implementation PageStateTestCase
 
+// TODO(crbug.com/675015): Re-enable this test on device.
+#if TARGET_IPHONE_SIMULATOR
+#define MAYBE_testScrollPositionRestoring testScrollPositionRestoring
+#else
+#define MAYBE_testScrollPositionRestoring FLAKY_testScrollPositionRestoring
+#endif
 // Tests that page scroll position of a page is restored upon returning to the
 // page via the back/forward buttons.
-- (void)testScrollPositionRestoring {
+- (void)MAYBE_testScrollPositionRestoring {
   // TODO(crbug.com/670700): Re-enable this test.
   if (!base::ios::IsRunningOnIOS10OrLater()) {
     EARL_GREY_TEST_DISABLED(@"Test disabled on pre-iOS 10");
   }
   web::test::SetUpFileBasedHttpServer();
 
   // Load first URL which is a long page.
   [ShellEarlGrey loadURL:HttpServer::MakeUrl(kLongPage1)];
 
   // Scroll the first page and verify the offset.
@@ skipping 18 matching lines @@
       assertWithMatcher:contentOffset(CGPointMake(0, kScrollOffset1))];
 
   // Go forward and verify that the second page offset has been restored.
   [[EarlGrey selectElementWithMatcher:web::forwardButton()]
       performAction:grey_tap()];
   [[EarlGrey selectElementWithMatcher:web::webViewScrollView()]
       assertWithMatcher:contentOffset(CGPointMake(0, kScrollOffset2))];
 }
 
 @end