Add ability to submit a form using javascript.

ios/web/public/test/web_view_interaction_test_util.h

Index: ios/web/public/test/web_view_interaction_test_util.h
diff --git a/ios/web/public/test/web_view_interaction_test_util.h b/ios/web/public/test/web_view_interaction_test_util.h
index 7004ec033c06dfd393bdb2d1e7778a1768f13d66..2981ecc42ce7e6430710b4ad00cbf99b07a8fb6d 100644
--- a/ios/web/public/test/web_view_interaction_test_util.h
+++ b/ios/web/public/test/web_view_interaction_test_util.h
@@ -19,5 +19,9 @@ bool TapWebViewElementWithId(web::WebState* web_state,
 bool FocusWebViewElementWithId(web::WebState* web_state,
                                const std::string& element_id);
 
+// Returns whether the form with |form_id| in the passed |web_state| has been
+// submitted using a JavaScript submit() event.
+bool SubmitWebViewFormWithId(web::WebState* web_state,
+                             const std::string& form_id);
 }  // namespace test
 }  // namespace web