Disable testScrollPositionRestoring on iOS 9.

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"
+#import "ios/testing/earl_grey/disabled_test_macros.h"
 #import "ios/web/public/test/http_server.h"
 #include "ios/web/public/test/http_server_util.h"
 #import "ios/web/shell/test/earl_grey/shell_base_test_case.h"
 #import "ios/web/shell/test/earl_grey/shell_earl_grey.h"
 #import "ios/web/shell/test/earl_grey/shell_matchers.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
@@ skipping 31 matching lines @@
 
 // Page state test cases for the web shell.
 @interface PageStateTestCase : ShellBaseTestCase
 @end
 
 @implementation PageStateTestCase
 
 // Tests that page scroll position of a page is restored upon returning to the
 // page via the back/forward buttons.
 - (void)testScrollPositionRestoring {
+  // TODO(crbug.com/670700): Re-enable this test.
+  if (!base::ios::IsRunningOnIOS10OrLater()) {

[Eugene But (OOO till 7-30), 2016/12/02 16:50:36]

Is it flaky on both device and simulator?

+    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.
   [[EarlGrey selectElementWithMatcher:web::webViewScrollView()]
       performAction:grey_scrollInDirection(kGREYDirectionDown, kScrollOffset1)];
   [[EarlGrey selectElementWithMatcher:web::webViewScrollView()]
       assertWithMatcher:contentOffset(CGPointMake(0, kScrollOffset1))];
@@ skipping 14 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