Add GetCurrentNativeController to webstate.

ios/web/public/test/native_controller_test_util.h

Index: ios/web/public/test/native_controller_test_util.h
diff --git a/ios/web/public/test/native_controller_test_util.h b/ios/web/public/test/native_controller_test_util.h
new file mode 100644
index 0000000000000000000000000000000000000000..62ed1a77301eb7030a909b4bf6e3ddd74c0e1bbd
--- /dev/null
+++ b/ios/web/public/test/native_controller_test_util.h
@@ -0,0 +1,21 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef IOS_WEB_PUBLIC_TEST_NATIVE_CONTROLLER_TEST_UTIL_H_
+#define IOS_WEB_PUBLIC_TEST_NATIVE_CONTROLLER_TEST_UTIL_H_
+
+#import "ios/web/public/web_state/web_state.h"
+
+@protocol CRWNativeContent;
+
+namespace web {
+namespace test {
+
+// Returns the native controller of the given |web_state|.
+id<CRWNativeContent> GetCurrentNativeController(WebState* web_state);
+
+}  // namespace test
+}  // namespace web
+
+#endif  // IOS_WEB_PUBLIC_TEST_NATIVE_CONTROLLER_TEST_UTIL_H_