[ios] EarlGrey test for scroll position restoration.

ios/web/shell/test/earl_grey/shell_matchers.mm

Index: ios/web/shell/test/earl_grey/shell_matchers.mm
diff --git a/ios/web/shell/test/earl_grey/shell_matchers.mm b/ios/web/shell/test/earl_grey/shell_matchers.mm
index 91412dcf7f08329bc7956ce3e52c13510dd73ee9..12b9ddb9a9cd8a5f55d9db7392b6f41f990b000f 100644
--- a/ios/web/shell/test/earl_grey/shell_matchers.mm
+++ b/ios/web/shell/test/earl_grey/shell_matchers.mm
@@ -19,6 +19,10 @@ id<GREYMatcher> webViewContainingText(const std::string& text) {
   return [GREYMatchers matcherForWebViewContainingText:text];
 }
 
+id<GREYMatcher> webViewScrollView() {
+  return [GREYMatchers matcherForWebViewScrollView];
+}
+
 id<GREYMatcher> addressFieldText(const std::string& text) {
   return [GREYMatchers matcherForAddressFieldEqualToText:text];
 }
@@ -44,6 +48,10 @@ id<GREYMatcher> addressField() {
   return web::webViewContainingText(text, webState);
 }
 
++ (id<GREYMatcher>)matcherForWebViewScrollView {
+  return web::webViewScrollView(web::shell_test_util::GetCurrentWebState());
+}
+
 + (id<GREYMatcher>)matcherForAddressFieldEqualToText:(const std::string&)text {
   MatchesBlock matches = ^BOOL(UIView* view) {
     if (![view isKindOfClass:[UITextField class]]) {