[ios] EarlGrey test for scroll position restoration.

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

Index: ios/web/shell/test/earl_grey/shell_matchers.h
diff --git a/ios/web/shell/test/earl_grey/shell_matchers.h b/ios/web/shell/test/earl_grey/shell_matchers.h
index 2ae057394e87c8ab6646d05b636c27ab57da992b..214bbfdf5daf28fab9f2f3f70673e89fdcce4be1 100644
--- a/ios/web/shell/test/earl_grey/shell_matchers.h
+++ b/ios/web/shell/test/earl_grey/shell_matchers.h
@@ -11,6 +11,9 @@ namespace web {
 // Shorthand for GREYMatchers::matcherForWebViewContainingText.
 id<GREYMatcher> webViewContainingText(const std::string& text);
 
+// Shorthand for GREYMatchers::matcherForWebViewScrollView.
+id<GREYMatcher> webViewScrollView();
+
 // Shorthand for GREYMatchers::matcherForAddressFieldEqualToText.
 id<GREYMatcher> addressFieldText(const std::string& text);
 
@@ -30,6 +33,9 @@ id<GREYMatcher> addressField();
 // Matcher for WKWebView containing |text|.
 + (id<GREYMatcher>)matcherForWebViewContainingText:(const std::string&)text;
 
+// Matcher for WKWebView's scroll view.
++ (id<GREYMatcher>)matcherForWebViewScrollView;
+
 // Matcher for web shell address field text property equal to |text|.
 + (id<GREYMatcher>)matcherForAddressFieldEqualToText:(const std::string&)text;