Refactor web shell integration tests utilities.

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/shell_matchers.mm b/ios/web/shell/test/earl_grey/shell_matchers.mm
similarity index 61%
rename from ios/web/shell/test/shell_matchers.mm
rename to ios/web/shell/test/earl_grey/shell_matchers.mm
index 52d9d614128fa7c1b17400b3be39ae044fdfa8fe..e0e37a1818067d389164e6c80388f7c3f3f8ab96 100644
--- a/ios/web/shell/test/shell_matchers.mm
+++ b/ios/web/shell/test/earl_grey/shell_matchers.mm
@@ -2,12 +2,20 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#import "ios/web/shell/test/shell_matchers.h"
+#import "ios/web/shell/test/earl_grey/shell_matchers.h"
 
+#import "ios/web/public/web_state/web_state.h"
+#import "ios/web/public/test/earl_grey/web_view_matchers.h"
+#import "ios/web/shell/test/app/web_shell_test_util.h"
 #import "ios/web/shell/view_controller.h"
 
 namespace web {
 
+// Shorthand for GREYMatchers::matcherForWebViewContainingText.
+id<GREYMatcher> webViewContainingText(NSString* text) {
+  return [GREYMatchers matcherForWebViewContainingText:text];
+}
+
 id<GREYMatcher> backButton() {
   return [GREYMatchers matcherForWebShellBackButton];
 }
@@ -24,6 +32,11 @@ id<GREYMatcher> addressField() {
 
 @implementation GREYMatchers (WebShellAdditions)
 
++ (id<GREYMatcher>)matcherForWebViewContainingText:(NSString*)text {
+  web::WebState* webState = web::web_shell_test_util::GetCurrentWebState();
+  return web::webViewContainingText(text, webState);
+}
+
 + (id<GREYMatcher>)matcherForWebShellBackButton {
   return grey_accessibilityLabel(kWebShellBackButtonAccessibilityLabel);
 }