Add content browser test for <optgroup> with 'display: none'

content/public/test/render_view_test.h

Index: content/public/test/render_view_test.h
diff --git a/content/public/test/render_view_test.h b/content/public/test/render_view_test.h
index 7f10ee864ac2bb836e30950dc3ab253a3f5a760a..52749d38b9cc450ceb98744d810b36ac9a71e1ba 100644
--- a/content/public/test/render_view_test.h
+++ b/content/public/test/render_view_test.h
@@ -73,6 +73,13 @@ class RenderViewTest : public testing::Test {
   bool ExecuteJavaScriptAndReturnIntValue(const base::string16& script,
                                           int* result);
 
+  // Executes the given JavaScript and sets the string value it evaluates to in
+  // |result|.
+  // Returns true if the JavaScript was evaluated correctly to an string value,
+  // false otherwise.
+  bool ExecuteJavaScriptAndReturnStringValue(const base::string16& script,
+                                          std::string& result);
+
   // Loads the given HTML into the main frame as a data: URL and blocks until
   // the navigation is committed.
   void LoadHTML(const char* html);