Add ability to submit a form using javascript.

ios/web/public/test/web_view_interaction_test_util.mm

Index: ios/web/public/test/web_view_interaction_test_util.mm
diff --git a/ios/web/public/test/web_view_interaction_test_util.mm b/ios/web/public/test/web_view_interaction_test_util.mm
index db4000300e857f21bb245d6c750af05017db6fbd..0892593c062af9f446a3938cc0ca0e822540e89e 100644
--- a/ios/web/public/test/web_view_interaction_test_util.mm
+++ b/ios/web/public/test/web_view_interaction_test_util.mm
@@ -15,7 +15,11 @@ using web::NavigationManager;
 namespace web {
 namespace test {
 
-enum ElementAction { ELEMENT_ACTION_CLICK, ELEMENT_ACTION_FOCUS };
+enum ElementAction {
+  ELEMENT_ACTION_CLICK,
+  ELEMENT_ACTION_FOCUS,
+  ELEMENT_ACTION_SUBMIT

[Eugene But (OOO till 7-30), 2016/08/26 21:48:05]

Optional NIT: Maybe add comma after last item to make suture changes cleaned?

[edchin, 2016/08/26 22:26:54]

I followed the convention already on the page. Seems reasonable to keep as is. 

+};
 
 // Returns whether the Javascript action specified by |action| ran on
 // |element_id| in the passed |web_state|.
@@ -32,6 +36,9 @@ bool RunActionOnWebViewElementWithId(web::WebState* web_state,
     case ELEMENT_ACTION_FOCUS:
       js_action = ".focus();";
       break;
+    case ELEMENT_ACTION_SUBMIT:
+      js_action = ".submit();";
+      break;
   }
   NSString* script = [NSString
       stringWithFormat:@"(function() {"
@@ -70,5 +77,11 @@ bool FocusWebViewElementWithId(web::WebState* web_state,
                                          ELEMENT_ACTION_FOCUS);
 }
 
+bool SubmitWebViewFormWithId(web::WebState* web_state,
+                             const std::string& form_id) {
+  return RunActionOnWebViewElementWithId(web_state, form_id,
+                                         ELEMENT_ACTION_SUBMIT);
+}
+
 }  // namespace test
 }  // namespace web